Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning

Technical shelters are the basic structures for storing electronic and technical equipment, and commonly used for telecommunication base station, windmill, gas station, etc. Due to their high internal heat load density and special operation schedule, they consume more energy than normal residential or commercial buildings. On the other hand, it is a big challenge to power the technical shelter in remote area where the grids are either not available or the expansion of grid is expensive. In order to minimize the energy consumption and obtain a reliable and cost-efficient power solution for technical shelter, this study will apply the net-zero energy concept into the technical shelter design. The energy conservation can be achieved by proper design of building envelop and optimization of the cooling strategies. Both experiments and numerical simulations are carried out to investigate the indoor environment and energy performance of the technical shelter. Finally, a wind-solar hybrid energy system is designed as an alternative power solution for technical shelter, in order to achieve a net-zero energy target.

This study aims to develop paraffin waxes based phase change material emulsion with low supercooling degree, which can be applied in a Thermal Energy Storage (TES) systems to maximize the use of natural heating and cooling sources via solar thermal collectors or evaporative coolers, and to raise the energy efficiency of the chillers operating at off-peak period. In this study, a kind of hexadecane-water emulsion with small droplet size was prepared and analyzed. The modified Multi-Wall Carbon Nano-Tube (MWCNT) particles were dispersed in emulsion as the nucleating agent to reduce supercooling degree. The MWCNT particles were modified with strong acids H

2

SO

4

and HNO

3

to increase the compatibility with the organic liquid. Thermal analysis of the hexadecane-water emulsions with well-dispersed MWCNT particles by Differential Scanning Calorimeter (DSC) indicated that the supercooling degree of emulsion was significantly decreased. The effective ranges of nucleating agent concentration were summarized which provided a promising way of improving the performance of system energy efficiency in TES systems.

This paper presents a combined heating, cooling, and power generation (tri-generation)system using sewage treatment digestion biogas according to the principle of energy gradient utilization technology. The tri-generation scheme adopts Lithium Bromide (LiBr) absorption cooling technology for office air conditioning, a biogas power generator, a heating system for digestion tanks. The performance analysis demonstrates that the scheme is practical in Hong Kong. Surplus cooling of the chiller is used to cool the inlet air of the generator for increasing the biogas power generator output. The electricity generation capacity can be increased by around 7 % annually owing to the inlet air cooler. For a case study of a local sewage water treatment work, the cooling capacity is equal to 422.72 MWh. The hot water meets the digester heating load at the same time. It is estimated that the economic payback period will be about 2 years.

District energy planning is an important approach to achieve a low-carbon target. However, district energy planning has not yet been incorporated in the official planning system, and there are still no clear standards and specifications defining the content and depth of low-carbon emissions reform. In this paper, low-carbon energy planning practices of several new districts are summarized and a general theoretical and practical framework for district energy planning is proposed. In addition, six key points of concern in the planning process are identified. These include low-carbon estimation and index control, overall planning of infrastructure, linkage between city planning and other special low-carbon eco-planning, investment and financing and operation modes, planning management mechanisms, and the construction of a growing energy system which is combined with a project schedule. Finally, it is suggested that energy planning should be standardized as soon as possible and planned comprehensively from the aspects of technology, commerce, and management, in order to realize the low-carbon target.

In recent years, with the improvement of the EMU performance, the EMU structure and material also had a series of changes. These changes can produce certain effect on the train body heat insulation performance. Heat insulation performance is the main factor of structure heat transfer, the motor train unit section heat insulation performance, and the factor for analyzing motor train unit operation energy consumption, which is of great significance on determining its air-conditioning load, avoiding the bad working environment (wall condensation and local high temperature) appear, and maintain the car comfortable thermal environment. This paper studies the practical operation heat insulation performance and studies a new generation of high speed EMU thermal performance design provide theoretical guidance and practical tool, which integrated by means of the theoretical analysis, numerical simulation, and experimental test methods, through the heat insulation performance of the EMU structure calculation and analysis.

This paper analyzes the structure of district heating system in Sect. 6.2 and indicates that it is a multistage heat transfer process. The energy quality decreases while the energy quantity remains if heat loss is ignored. In Sect. 6.3, heat sources with different temperature levels, which mean the energy quality, are analyzed. In Sect. 6.4, entransy, a physical quantity which represents the heat transfer ability, is used to describe the energy quality of heat in district heating system. The heat sources must meet the need of both energy quantity and entransy. Then the thermal analysis is carried out to prove the entransy dissipation is related to power generation and it must be reduced. Different methods are suggested for different result of calculation. In the last chapter, a case in Chifeng city is studied to test the theory of this paper.

As a type of groundwater heat pump, single-well groundwater heat pump systems have received much attention in recent years due to its efficient properties. In this chapter, a sand tank experiment system of single-well systems is designed and set up in Harbin Institute of Technology. The aim of this study is to find the relationship among the temperature of outlet water, the power of the single-well systems, the thermal transfixion, and the distance between pumping screen and injection screen. The data obtained demonstrate that the mean temperature of outlet water and the power are increased, and the coefficient of thermal transfixion is decreased when the distance between pumping screen and injection screen is raised. The distance between pumping screen and injection screen is an important factor in the single-well systems that can affect the power of the system directly. The coefficient of thermal transfixion is an appropriate parameter to evaluate the single-well systems.

The horizontal ground heat exchanger (HGHE) with slinky-coiled pipes recently has been used as a heat source/sink for geothermal heat pump systems because of the significant lower initial cost. A simplified heat transfer model suitable for engineering design of the slinky HGHEs is developed. The model is based on the one-dimensional transient heat transfer in an infinite medium, considering the influence of the tube length per area and the different effects of long-term mean load and short-term intermittent load. A case study is carried out to design the HGHE size by using the proposed model. Some key factors which influence the performance of the HGHE are also discussed such as the thermal properties of the ground and the pipe length per area.

In the paper, through a District cooling project in Chongqing, optimized design and evaluation methods of secondary loop network system are concluded, by optimizing the design of the secondary ring-shaped pipe network, analyzing hydraulic conditions in the case of part load rate (100, 75, 50, and 25 %) and the most unfavorable accident conditions of various options, evaluating various schemes in terms of energy efficiency, economy, and reliability.

Although the seawater source heat pump district heating system is often regarded as a renewable energy utilization system, it cannot be guaranteed to obtain the energy-saving effect. The authors provided an energy-saving judgement method for the electric-driven seawater source heat pump district heating system over the conventional boiler house district heating system in former research. However, many factors will influence the energy efficiency of the system. In order to enhance its energy efficiency and make the best use of the system, detail analysis of those factors is conducted in the paper. First, an energy-saving potential evaluation model is derived for the system with part-time operation mode. Then all the factors influencing the energy efficiency of the system are ascertained and analyzed. These factors include the electricity generation efficiency, energy performance of seawater source heat pump units, the seawater temperature, the energy consumption of the seawater pump, the local outdoor air temperature, and the heating district radius. The research results are expected to provide clear directions for the seawater source heat pump system to raise its energy efficiency.

The authors systematically summarized the research on the radiant cooling system in recent years. On the basis of a brief introduction of the radiant cooling system and its working principles, the advantages and disadvantages of the system were concluded compared with the conventional air conditioning system. The reasons for the slow development of radiant cooling system in China and its future trend were then discussed. It was suggested the solution to the condensation problem be focused on collecting and discharging the condensation water. This measure will not only improve the capacity of the radiant cooling system but also expand the application scope of the radiant cooling system.

This paper analyses the heat storage processes in HVAC system and uses the entransy method to calculate the equivalent thermal resistance of energy-storage heat exchangers. Analogous to normal heat exchangers, unmatching coefficient has been introduced to the analysis of energy-storage heat exchanger. It also illustrates the unmatching extent’s influence on thermal resistance for convection in heat absorption process and heat release process under constant temperature boundary condition and constant heat flux boundary condition, respectively. Taking the daytime-heat-absorption and nighttime-heat-release of floor as an example, the unmatching coefficients and proportions of the three parts resistance are analyzed, and the main factors restricting thermal storage performance could be obtained. The results are helpful for the design and optimization of the energy-storage heat exchange system.

Conditions and screening criteria of chemical heat storage material are introduced in the paper. Hydroxide is chosen as the research object. The thermodynamic parameters of the material have been calculated using HSC chemistry software. The main parameters are steering temperature and equilibrium constant. The results show that steering temperature of calcium hydroxide is 798 K, and its enthalpy difference is 100 kJ/mol. In the vicinity of this temperature, Gibbs free energy changes from the positive to the negative, indicating that above this temperature, the reaction can be spontaneous. Calcium hydroxide is a kind of ideal heat storage material as a large-scale storage of solar energy.

A performance testing experiment platform of heat pump water heater of CO

2

trans-critical cycle whose evaporator and gas cooler are both sleeve type heat exchanger has been designed and then constructed. CO

2

refrigerant charge amount of the system is 1.23 kg. System performance has been researched by adjusting the degree of opening of the expansion valve and controlling the flow of water of the gas cooler. The results show that: The system can provide hot water of 65 degrees when its cop is 3.2. And hot water of above 80 degrees can be obtained when system’s cop is above 2.0. The water flow of the gas cooler has the greatest impact on the cop of the system, the temperature of water out of the gas cooler, and the exhaust pressure of the system. With highly efficient heat exchanger, the temperature of water out of the gas cooler could be increased while compressor discharge temperature is remained the same. So when the system provides high temperature water, it could run in higher cop.

This paper aims to optimizing the conjunctive use of sewage source heat pump technology and solar hot water heating technology and improving the drawbacks when they are, respectively, applied. By adopting key technologies such as cooperation technology of sewage source heat pump technology and solar hot water heating technology, efficient phase change technology, scientific operation strategies, continuous automatic control of each equipment and others, the system realizes the efficient operation of sewage source heat pump units and solar hot water heating system, storage and delay of energy, full utilization of peak and valley time price policy which enables the system to gain the best heating effect and efficient operation of each equipment. We conduct a test and statistical analysis on the indoor comfort parameter, electricity, and water consumption of major equipments and the performance change of equipments at operation time for the system, and continuously optimize design conception for providing significant reference and guidance to the future field of renewable energy, finally completing the transition from nonrenewable energy to renewable energy.

Combined district heating is one of the development trends of central heating in China, mainly due to its high flexibility, reliability, and energy saving potential. In this paper, we analyzed the applicable operation regulation ways for a combined district heating system with combined heat and power (CHP) plant as the basic heat source and two large-scale coal- and gas-fired boilers in primary heating network as the peak-shaving heat sources. Four operation regulation ways were studied in the paper, including quality regulation in different phases (alternative 1), quality–quantity regulation (alternative 2), quality regulation before combined heating and quality–quantity regulation after combined heating (alternative 3), quality regulation before combined heating and quantity regulation after combined heating (alternative 4). The results indicate that alternative 1 is constrained by the design supply water temperature of CHP plant. Alternative 2 has a relative high possibility to lead to hydraulic maladjustments. Alternative 4 requires high management capabilities and sound automatic control devices, therefore alternative 3 is recommended as the most applicable operation regulation way.

This article adopts the method of ‘Local-Global optimization’ to analyze the energy system of ice storage air conditioning of China World Trade Center Phase 3 by the tool of eQuest energy consumption simulation software. We found the influential factors of the air conditioning system through the actual measurement and simulation analysis results of energy consumption of air conditioning system. Then we adopt the method of ‘Local-Global optimization’ from the Angle of energy system and combine with the actual condition of the ice storage air conditioning, we make three optimization scheme, which are reducing cooling water temperature difference, adopting variable flow rate chilled water pumps, and improving the fan delivery ratio. And then we analyze energy consumption change of three schemes and find out the interactive effect of the local system. Finally, we sort the energy saving effect and find out the optimal overall optimization scheme.

An experimental study was conducted on pool boiling heat transfer and in-tube condensing heat transfer in different working conditions. Analysis the total heat transfer, so as to verity weather tank can meet remove the heat amount produced by electric heating equipment in steam generator. Also the influence of each experimental parameters was analyzed on heat transfer coefficient, as well as the pool boiling heat transfer of boiling scene. The result shows that, steam in tube was condensed into saturate water after 3 min 2 MPa and 2.4 m in 5 MPa. This paper analyzes the relations among pool boiling heat transfer coefficient, in-tube condensing heat transfer coefficient, and total heat transfer coefficient. It concluded that, for 2 MPa, pool boiling heat transfer coefficient was the highest. The contrast of system total heat transfer capacity and pool boiling heat transfer capacity shows that their error was in the range of rationale, which meant the heat transfer capacity of cooling tank can remove system residual heat.

A novel solar-powered ejector air-conditioning system with a nominal capacity of 5 kW cooling is described in this chapter. The system comprised an evacuated tube solar collector system, an ejector cooling system, and an MEPCM cooling storage system. The full size system has been laboratory tested, and the results are in good agreement with CFD simulation. A COP of up to 0.32 is obtained for the ejector cooling system during the test at the boiler temperature around 90 °C. Coefficient of performance of is up to 0.16 is predicted for the integrated system in operation. Guidelines for the design of system components based on the results of computer modeling and laboratory testing is given. Related correlations between these parameters will be obtained and presented in an easy step-by-step manner, in order to facilitate design and integration of system components for various applications. These will include analytical equations to match climate conditions and building air-conditioning load.

A residential building of 11-story was chosen as the objective buildings. Load characteristics under continuous and intermittent operating condition were analyzed by DeST software. Soil temperature variation of single ground-source heat pump under different operating condition was simulated by GeoStar software. Thermal energy storage duration of the solar-assisted ground-source heat pump system was further discussed on the basis of geothermal temperature balance. Results show that the intermittent operation has great influence on load characteristics, soil temperature, and energy storage period. Building function and system operating mode should be paid much attention during the engineering practice.

Energy is an important material basis for the survival and development of human society, China’s rapid economic growth accompanied by low efficiency of energy utilization, the pressure of the rapid rise in carbon emissions, reasonable measure, and a comprehensive analysis of energy efficiency, which is a clear understanding of an important part of China’s current economic development, energy use and carbon dioxide emissions overall efficiency of the situation. Economic development is the most important determinant of the increase in carbon dioxide emissions in China, but we cannot mitigate carbon dioxide emissions by slowing down economic growth, we should focus on reducing energy intensity, increasing the consumption of low-carbon energy. Therefore, from the point of view of regional differences, through the analysis of the regional characteristics of the energy consumption and carbon emissions, measuring 2005 to 2011, China’s 30 provinces and municipalities energy efficiency, building energy efficiency index of different dimensions, compare the energy efficiency differences, fluctuations, balance of China’s eastern, central and western regions and provinces, and do the energy efficiency forecasting at the same time. Found that there is an obvious persistent regularity in the evolution of the energy efficiency of other regions. The energy efficiency of the various regions will continue to maintain growth. It has a very important practical significance to achieve corresponding to different regions of the improvement of energy intensity and energy structure of the low-carbon target.

The latest studies indicate that an investment in a better indoor environment is a profitable one, even with very minor productivity changes. In addition to the indoor environment, the functionality of the workspace significantly affects the productivity of employees. Often a compromise must be made among the needs of the employee, team, and organization when arranging workspaces. Organizational changes in most companies are continuous and require flexible changes in work methods and workspaces. Layout changes in workplaces are a rule, not an exception. Due to management reorganization, changes in business models, and technological innovations, companies may already change their workplace interior layout once a year. Churn cost is often one of the highest operating costs in modern offices being 330 to 2000 € per moved person a year.

A laboratory experimental study was conducted to investigate the energy performance of a total heat recovery unit using a polymer membranes heat exchanger. The study was conducted in twin climate chambers. One of the chambers simulated outdoor climate conditions and the other simulated the climate condition indoors. The airflows taken from the two chambers were connected into the total heat recovery unit and exchange heat in a polymer membrane foil heat exchanger installed inside the unit. The temperature and humidity of the air upstream and downstream of the heat exchanger were measured. Based on the measured temperature and humidity values, the temperature, humidity, and enthalpy efficiencies of the total heat recovery unit were calculated. The experiment was conducted in different combinations of outdoor climate conditions simulating warm and humid outdoor climates and air-conditioned indoor climate. The test was also conducted in isothermal conditions to observe the moisture transfer performance of the polymer membrane heat exchanger. The results of the experiment shows that total heat recovery equipment tested can recover up to 60 % of the total heat from the ventilation air. Around 87 % of the recovered total heat is latent heat that comes from the moisture transfer.

When radiant systems are installed in highly glazed rooms large amounts of solar radiation directly hit the cooled surface; this specific behavior of radiant systems in this situation should be studied in order to modify the procedure that is traditionally applied to design radiant cooling systems. Furthermore, radiant systems behave in different ways depending on their thermal mass. Based on previous researches, a model is proposed in this work to determine the conversion of heat gains into cooling loads; the model is specifically adapted to highly glazed buildings, and is differentiated for low and high thermal masses radiant systems. A numerical model is developed to provide a calculation example that confirms the proposed procedure.

This paper describes the application of dynamic energy simulation in order to analyze the application of thermostatic radiator valves (TRVs) on four existing multi-family buildings that are served by a district heating network. A complex and detailed energy model of each case study was defined by means of the energy simulation code EnergyPlus, in order to predict the effect of the employment of TRVs on the heating energy consumptions. The building geometry and envelope characteristics were extracted from the building energy performance certificates; each room equipped with a radiator was defined as a single thermal zone in order to simulate the effect of the TRVs. Measured energy rates and water flow rates of the district heating were used to calibrate the numerical model. In the calibrated model, the impact of TRV control as well as the consequent heat transfer between neighboring rooms were taken into account. Each case study was simulated with and without TRVs. The simulation results show that the use of TRVs can bring a reduction on total heating energy consumption ranging from a minimum of 5 % to a maximum of 20 %.

Operable windows provide occupants’ ability to control over local environment and satisfy human’s expectation to access to outdoor environment. Operation strategies for operable windows can have significant impacts on indoor thermal comfort and energy consumption of building performance. It is not uncommon that building facility managers complain that operable windows were left open in buildings with a conventional HVAC system. However, optimum control strategies of window operation can improve thermal comfort and reduce energy consumption for building using natural ventilation or mixed mode ventilation. The study focuses on the investigation of the impacts of window operations on building performance for different types of building systems including natural ventilation, mixed mode ventilation, and conventional HVAC systems in a medium-size reference office building. Building performance simulation tool―EnergyPlus is used to simulate window operations for each system in three different climates. Various control strategies of window operations for building operation systems, implemented using (EMS) in EnergyPlus, are evaluated based on the criteria of thermal comfort and energy consumption. The results highlight the impacts of window operations on thermal comfort and energy use and identify that hybrid ventilation for perimeter zones has 12–20 % saving potentials of annual HVAC site energy consumption.

A number of trends are stimulating interest in the usage of filtration and air cleaning as an adjunct to the environmental conditioning of buildings. These include escalation of energy costs, heightened awareness about acceptable IAQ, aging of the commercial building inventory, numerous revisions and addenda to ventilation standards and building codes, and green building/sustainability initiatives and energy tax credits. A field study was performed on established installations of particulate and gas-phase filtration in and around Atlanta, Georgia (USA), and included a variety of building types and usage and evaluated environmental conditions and airborne contaminants. The study was undertaken in two parts with Phase I being to establish and finalize test and measurement protocols and a Phase II for field investigation. This paper provides a summary of both Phases, including characteristics of untreated outdoor air, and air cleaning with particulate filters and gas-phase air filtration. Overall, there was a TVOC reduction of 38−74 %, 0.5 μm particulate removal efficiency of 28−95 %, and an ozone removal efficiency of 100 %. Each building had annual operational cost savings ranging between US$10,000 and US$800,000. The field study is intended to establish the parameters of dilution air compared with similar characteristics of air treated with particulate and gas-phase filtration. The field study demonstrated that filtered air can meet or exceed the IAQ level from simple dilution with outdoor air. The study also documents the comparable energy savings as a result of a reduction in outdoor air ventilation rates and significant control of specific contaminants of concern regarding occupant safety and building security.

Aqua ammonia absorption refrigeration system involves design of condenser, evaporator, absorber, heat exchange equipment. Absorber is very important equipment in refrigeration system. Aiming at different sizes transversally grooved tube (TGT), a series of experiments are carried out to find approach which can enhance absorption efficiency and to choose an optimal tube type. The experiment results show that ammonia solution can absorb the more ammonia gas following increase of pressure difference and velocity of cooling water inside tube, therefore mass transfer coefficient becomes larger. When spray density of ammonia solution outside tube alters from small to large, mass transfer coefficient increases firstly and then decreases, so that gets a optimum. The group experiment results indicate that transversally grooved tube have better mass transfer ability than smooth tube. For example, when spray density of solution is 472.1 kg m

−1

h

−1

, mass transfer coefficient of transversally grooved tube rise by 109.6 % compared to smooth tube. A common law is discovered during three groups of experiment. Different sizes of TGT have different ability to absorb ammonia gas, and Number 2 tube is the best tube considering absorption efficiency. Flow patterns of blend and vortex flow are compared among three transversally grooved tubes with solutions flowing through grooves. The reason why series of TGT of different sizes have different absorption efficiency is obtained by means of analysis on flow model ammonia solution flowing through TGT.

A lot of hazardous gases will be produced during sludge composting, if treated improperly, pollution may be caused to the environment. Biofilter process is an effective deodorizing method. But the resistance of biofilter materials that in turn have critical effects on whether the ventilation system of the workshop can operate normally. The research group conducts researches on resistance characteristics of four commonly used filter materials in a view to helping similar sludge composting plants in designing ventilation system, choosing fans, and managing operation. The results of the researches show that biofilter material is of the law of high-speed non-Darcy flow, their resistance characteristics are related with the characters, superficial velocity, bed thickness, etc., of the filter material, about which the empirical computation formulas are given.

A variety of data centers have come into being as required by the continuous development of social network and information technology; meanwhile, wide concern has been aroused about the issue on data center’s high energy consumption in which the air conditioning energy consumption accounts for more than 40 %. Thus, it is of great importance to achieve the energy conservation of air conditioning system in data center. According to the new requirement for IT equipment performance and new design range of temperature in data center, this paper presents a full fresh air ventilation and cooling scheme for ambient temperature control of data center, which, without mechanical refrigeration equipment and under the premise of meeting the design requirements for ambient temperature, has greatly reduced the energy consumption and provided a new idea for the design of next-generation data center.

The air distribution characteristics formed by an “air curtain” ventilation approach are presented. The design principle of this novel air distribution pattern is investigated. A design example is introduced; meanwhile, the design programs and effectiveness evaluation were carried out. The current results show the air curtain ventilation (ACV) is a particular air distribution to combine the mixing ventilation and displacement ventilation together. In additional, the air lake phenomena of occupied zones resembles displaced air movement in some extent. The design process of the air distribution formed by ACV is demonstrated.

New-type cooling ceiling capillary radiant panels are more convenient in installing and much easier in ensuring the quality of produce than the traditional capillary radiant panels. The present study compared the cooling performance between the new-type cooling ceiling capillary radiant panels and overseas traditional capillary radiant panels by numerical simulation and experimental test. The results indicated that new-type cooling ceiling capillary radiant panels are more energy-saving and convenient in use than traditional capillary radiant panels. It provides some scientific references for the application and popularization of the new-type cooling ceiling capillary radiant panels.

Reversibly used cooling towers (RUCT) are used to extract heat from atmospheric to water. In this study, the factors influencing the value of Lewis number in a RUCT are analyzed by experimental investigation. The results show that Lewis number increases with the increase of water−air flow rate ratio. When the water−air flow rate ratio is constant, the Lewis number decreases with the increase of inlet water temperature and inlet air wet-bulb temperature, increases with the increase of inlet air dry-bulb temperature and water sprinkle density. This research offers a fundamental basis for studying heat and mass transfer characteristics in a cross flow reversibly used cooling tower and practical application.

Water source heat pump system is a green air-conditioning system which has high efficiency, energy saving, and environmental protection, but inappropriate design of the system type of water intake will impact on energy efficiency ratio of the system. In order to evaluate the efficiency of heating and cooling source use of water source heat pump system, the impacts of temperature, flow and static head of cooling water on the energy efficiency ratio of water source heat pump system are analyzed in this paper. The cooling load of air condition and parameters of cold water are set as control objectives, and the analytical model of energy efficiency ratio including the energy consumption of cooling water system and cooling water unit is proposed. The running energy efficiency ratios of two types of water source heat pump system are analyzed by using this model (direct heat transfer that surface water flowing into condenser directly, indirect heat transfer through plate heat exchanger). The results show that the impact of change of cooling water temperature on energy efficiency ratio is bigger than the change of static head of cooling water system.

This study applied experimental methods to gather airflow turbulence information by different anemometers in a full-size MD-82 aircraft cabin, including turbulence energy spectrum densities (TESD) at the sidewall diffusers and time-average flow fields. The results indicated that the large range of TESD of airflow must be measured by high-frequency equipments, such as hot-wire anemometers (HWA), at 50 kHz, and for flow fields, three-dimensional ultrasonic anemometers (UA) were needed to obtain accurate velocity magnitudes and turbulence intensities (TI) at the cross section of one row in the cabin. This investigation verified that TI had a reciprocal relationship with mean velocity and calculated the regression equations.

To control the products quality and ensure the benign development of HVAC&R industry, it is of great importance to test and measure the quality of HVAC&R products. Due to the reality of diversification of HVAC&R products, unifunctional platform cannot meet the needs of test. In this paper, a multifunctional testing platform was founded, which can complete various performance tests of different kinds of HVAC&R products. Based on this multifunctional testing platform, a measurement and control system were designed. The software of this system was developed with VB, and different kinds of communication protocol were used to achieve the connection between the computer and instruments of data acquisition and control. Several key points such as data acquisition, data storage, and real-time curve were described in this paper. A period of use shows that, the multifunctional testing platform can achieve the various performance tests of various different kinds of HVAC&R products with good reliability, stability, and precision. Also, it indicates that the structure and functions of this system were suitable.

The air leakage of duct is an important indicator to inspect the quality of ventilation and air-conditioning system project. The strength and tightness of air duct in the ventilation and air-conditioning system is one of the important indicators to measure the processing and production quality of duct. According to the relevant provisions of the specification, the duct should be tested for its tightness according to the system category after the production and installation. In the construction, the tightness test of duct system is more cumbersome, and there is some difficulty in operation to really do well in the air leakage test of the duct system, as the testing task needs not only special testing equipment, instruments and, meters, but also certain technicians. This paper introduces a simplified air leakage testing method in accordance with the specification. The application and inspection in practical projects prove that the method is a correct and simple test method with strong operability.

Based on energy conservation principle and heat transfer mechanisms, a set of dynamic model was established for an indirect district heating system. Dynamic start-up process under ideal condition was simulated and the influence of heat loss from piping network, make-up water and intermediate heat exchange station, and radiator area surplus on the dynamic characteristics of the system was discussed. Dynamic process without control was simulated under the hourly outdoor temperature measured in the days from February 13 to 19, 2012. To overcome the obvious indoor temperature variation with outdoor temperature, four PI control strategies were proposed. The dynamic characteristic and energy consumption of the system operated under these four control strategies were discussed. It is found that the control strategy 3, controlling the fuel flow rate, and water flow rate in the first loop not only produce stable working performance but also obtain considerable energy saving potentials. These results are very helpful to realize the dynamic characteristics of the indirect district heating system and to select suitable control strategy and optimal performance.

An appropriate control logic is very important to optimize the performance of a two-stage compression heat pump system. In this paper, a numerical simulation model of two-stage compression heat pump system with intercooler was first presented and then validated by comparing simulation results with measured data. In addition, the model was used to analyze the performance characteristics of the heat pump, according to the superheat at suction line of the high-stage compressor and injection point, with frequency of low-stage compressor varying from 30 to 80 Hz. The simulation results showed that the heating capacity increased linearly with an increase of frequency of low-stage compressor, and the optimum heating capacity and COP were determined when the quality of the injection point was very close to unity. It was suggested that the superheat at the injection point was kept at 2 °C by controlling the 2nd EEV’s opening, and the frequency of low-stage compressor was adjusted to meet the heating command of the user during space heating.

The experiments of one counter-flow direct evaporative cooling (DEC) system have been carried out to investigate the characteristics of heat and mass transfer between air and water in temperature range of 20 to −7 °C. Three kinds of driving forces in DEC are defined and adopted in this paper, while novel evaluation indices are proposed to evaluate the performance of the process. Experimental data under different parameters of air and water are compared and analyzed. The results show that DEC in unconventional-temperature range is more sensitive to driving forces than in normal temperature range. Consequently, energy performance of DEC would be highly influenced driving forces. Furthermore, to making full use of cooling potential of DEC in lower temperature range, a novel evaporative cooling and heat pump-driven liquid desiccant hybrid system is proposed and its performance has been preliminarily studied.

A novel unidirectional loop hot water heating system has been proposed in order to improve the adaptability of the district heating system heat load growth and improve system hydraulic stability. There are four parts in this paper. The composition of the new system was introduced in this paper firstly. The hydraulic design and condition were discussed secondly. Then the thermal condition including node temperature calculation and local regulation mode were studied. In the end, a case study was done to analyze the hydraulic and thermodynamic condition during the operation. The results showed that the new system had straightforward hydraulic and thermal condition. Through this research, some reference could be provided for the practical application of the unidirectional loop hot water heating system.

The jet entrainment from motional air to the ambient stationary air is one of the important characteristics for jet airstream. Entrainment can change its internal distribution of temperature, velocity, jet flow, and energy distribution, which are closely related with the engineering design of ventilation and air conditioning. Thereby, it is significant to quantify the amount of jet entrainment which is caused by nozzle jet from the ambient air in an air-conditioning room. Basing on the basic theory of fluid mechanics, we had proposed a measurement method of jet entrainment by the tracer gas. In this paper, we have made an experimental study in a constant temperature and humidity laboratory to measure and calculate the entrainment for the air conditioning jet motion, compared the results to the traditional method of velocity measurement, and predicted the related factors of the jet entrainment.

The air distribution characteristics formed by fabric air dispersion system (FADS) are investigated by visualization experiment in a full-scale room. The airflow structure of FADS was presented and verified by this experiment, and compared with the traditional airflow patterns. The jet supply velocity and the outlet orientation are choosing as major factors influent on airflow field of FADS. A semi-empirical expression was given to calculate the jet deflection angle causing by different jet supply velocities. Meanwhile, the induction and flow junction phenomena are analyzed under different combination of outlet orientation, and the experimental results show that this induction is beneficial in design and application of FADS in practical engineering. The current experimental study and its results are helpful for using fabric air dispersion method in HVAC system.

Ground-coupled heat pump (GCHP) has been widely used as an energy-saving and environment-friendly heating and cooling system. But for the buildings in cold regions, because the heat extracted from ground is much larger than the heat rejected into it, the ground cannot keep thermal balance and consequently the soil temperature will decrease year by year. With the decrease of the soil temperature, the ground-coupled heat pump system declines in performance or even stops running after a longtime operation. This paper aims at specifically revealing the phenomenon of soil temperature decrease in cold regions by an integrated dynamic simulation. 10 year’s dynamic soil temperatures of GCHP used for just heating and for both heating and cooling in four typical cities are simulated and compared. The results show that the office building using GCHP just for heating has a severer soil temperature decrease: the temperature drop is respectively 11.7 °C in Harbin, 9.6 °C in Shenyang, 9.0 °C in Beijing, 5.8 °C in Zhengzhou. For the system with both heating and cooling, the soil temperature drop is 8.2 °C and 3.4 °C in Harbin and Shenyang, while the soil temperature rise is 0.02 °C and 5.5 °C in Beijing and Zhengzhou. The results of simulation are valuable for the design and operation of GCHP system applied in cold region.

The imbalance of heat extracted from the soil by the ground heat exchangers (GHEs) in winter, and rejected into it in summer is expected to affect the long-term performance of ground source heat pump (GSHP) in areas of southern China. This chapter presents a new operation mode to resolve this problem that in summer night the intermittent operation of GHEs with the cooling tower as the supplemental heat rejecter of GSHP system and in transition seasons the coupling operation of cooling tower combined with the GHEs. The practical analytical model of GHEs based on the line-source theory is established. The computer program based on established model is developed to do the feasibility analysis under the proposed operating mode for a GSHP system in Nanjing of southern China. The results indicate that the imbalance problem of the rejected/extracted heat for the GSHP system in Nanjing of southern China is effectively resolved. In addition, under the proposed operating mode the COP of heat pump unit can be improved, design capacity of cooling tower can be reduced and utilization rate of cooling tower throughout the year can also be increased. The results can improve the energy efficiency of GSHP system.

This study has the objective to study the optimized configuration of cooling source of a districted natural gas Combined Cooling Heating and Power (CCHP) system, and as a result, models of cooling source, distribution and system energy efficiency were established. Through a C# program, hourly simulation of operation quantity, power consumption, and equivalent thermal coefficient (ETC) of the cooling system during May to October was conducted under three configuration strategy schemes. The results revealed that when the waste heat of CCHP system was properly utilized, increasing the number of electric chiller could increase primary energy utilization rate. Scheme One with the most electric chiller units (15 units) consumed the most power, but had the highest ETC of 1.031 (mean),which was, respectively, 0.268 and 0.346 higher than that of Scheme Two with 11 electric chiller units and Scheme Three with most steam BrLi absorption chiller units (nine units). Scheme Three needed the most steam which led to the least electricity generated. Although in this scheme, the electric chillers consumed the least power, the average remaining electricity of the CCHP system was the lowest (64,992.4 kWh), which was 21,441.9 and 6,233.8 kWh less than that of Scheme One and Scheme Two. ETC of the three schemes (1.031, 0.763, and 0.685, respectively) were much less than that of electric chiller (2.630), which meant that the main reason for the decrease of primary energy utilization rate of the cooling system was due to low primary energy utilization rate of the distribution system.

Indoor air temperature, floor temperature, and wall surface temperature were measured when lightweight radiant floor cooling combined with underfloor ventilation (LRFCUV) air conditioning system and heavy radiant floor cooling combined with underfloor ventilation (HRFCUV) air conditioning system operated. And indoor air temperature field, heat-transfer capability, and thermal comfort were analyzed. Experimental results show that LRFCUV air conditioning system started up faster than HRFCUV air conditioning system. When the system reached stable condition, net radiant floor heat quantity of HRFCUV air conditioning system was larger than that of LRFCUV air conditioning system, and thermal comfort of HRFCUV air conditioning system was better than that of LRFCUV air conditioning system.

This work describes a large reclaimed water source heat pump system, and elaborate on the composition of the system and its design principles. We make an energy planning for its service area and in accordance with the progress of the project’s investment and construction, the system is divided into two stages: the phase I with the energy bus system; the project of phase II uses centralized indirect district heating system, it uses a two-stage heat pump unit in order to reduce the temperature lift of the main heat pump. The whole system adopts the distributed circulating pump power system. The work also analyzes the heating capacity of the system, when the phase II project is completed, the system can provide hydronic heating water with the supply and return water temperature of 55/15 °C, and meet the hydronic heating demand of 8 million square meters of residential buildings. Calculated the coal consumption indicators per unit area in a heating period and compared with the regional boiler room heating system, 8 million square meters of district heating in a heating season can save 53,161 tons of standard coal. The coal saving rate reaches 39.32 %.

The heat storage capacity of the existing air conditioning cooling reservoir is not enough due to the increase in equipment and personnel. The problem of insufficient heat storage capacity can be solved by using phase change energy storage technology. In this paper, the model experiment of air conditioning cooling water reservoir is established. Different number of phase change heat storage modules (PCHSMs) of 0, 104, 208, 312, 412, 512, and 614 are separately put into the reservoir, and then the heat storage capacity of the reservoir is tested. The test results indicate that it takes 17.37 h for the outlet water temperature of the reservoir to rise from 19° to 37° with 0 PCHSM, then the heat storage capacity of the reservoir increases as the number of PCHSMs increases. Comparing with the 0 PCHSM, the heat storage capacity of the reservoir increased 42.25 % with 614 PCHSMs. The heat storage capacity of reservoir can be obviously improved by using of PCHSMs. Therefore, the phase change heat storage type air conditioning cooling reservoir (PCACCR) is a meaningful way to guide reconstruction of existing reservoirs and construction of new reservoirs.

The typical building in severe cold region was selected. The form of the complementary heating system on solar-ground source heat pump and heating network was proposed in this paper. The simulation model of the complementary system was established by TRNSYS which is transient simulation software as design platform. The various components were designed. The matching relationship among the components which including the solar collector and the ground heat exchanger and the storage tank and the heating network were researched. The results of the simulation demonstrate that the average COP of the heat pump unit is 4.04, and monthly average COP is 4.0 or more. The heat taken from the soil is reduced by 30 % in the auxiliary role of solar. Under the same of supplying heat, when the area of solar collector is increased by every 1 m

2

, and the length of ground heat exchanger can be approximately decreased by 5.6 m. When the matching relationship of the volume of the storage tank and the solar collector area is 60–80 L/m

2

, and the efficiency of the water tank is highest in the solar short-term heat storage system.

The bigger buried pipe spacing will increase buried pipe surface area, go against to save land and initial investment; the smaller buried pipe spacing will cause obvious thermal interference phenomenon between adjacent buried pipes, go against to heat transfer of the buried pipe heat exchanger and stable operation of the system. In the actual operation process of heat pump system, the actual heat load is often less than the design load, so we can try to open different buried pipes, adjust the actual operation spacing, to reduce the heat interference phenomenon between adjacent buried pipes, make for the operation of the heat pump system. The experiment was done in a villa Ground source heat pump system, in which kind of buried pipe spacing system running more energy saving was analyzed. Conclusions as follow: the bigger buried pipe spacing the higher unit and system COP, Spacing for the 3.6 m, System COP is 3.4, unit COP is 5.1; Spacing for the 5.4 m, System COP is 3.5, unit COP is 5.3; Spacing for the 7.2 m, System COP is 3.6, unit COP is 5.5; Spacing for 5.4 m system COP is 2.9 % higher than spacing 3.6 m, unit COP is 3.9 % higher; Spacing for 7.2 m, System COP is 2.8 % higher than spacing 5.4 m, unit COP is 3.77 % higher; So, at the same load, we can adjust running spacing by opening different buried pipe wells to improve COP of system and unit, to save energy.

This study analyzed the current electricity consumption of heating exchanging stations in China. By testing the pressure drop of each opponent and the operating condition of pumps, the conclusion was that the largest amount of potential energy saving was inside of stations. The improper selection of pumps, heat exchangers, and pipes was the important reason to cause extra energy loss.

The research, based on the rural traditional Kang which is a kind of heated fixed bed, studied the thermal property of the Kang surface through the combination ways of experiment and computer simulations. The main research focused on the Kang surface temperature within 24 h, the percentage of heat amount transferred into the indoor from the Kang, the temperature drop delay of the Kang surface because of the Kang’s thermal storage capacity, and the temperature fluctuation of Kang surface due to different inlet size of smoke entering the Kang, the purpose is to provide reference for integrated heating system within the rural indoor room. The research is based on the theoretical mathematical models and experimental data fitting models, using VB programming language to develop software to simulate the Kang surface temperature within 24 h under different conditions, at the same time using the Fluent software to simulate and revise the mathematical models based on VB programming language. The simulative results were compared with the experimental measured ones. The results show that the temperature distribution of the Kang surface is not uniform. Existing phenomenon is that the temperature of Kang surface closed to the smoke inlet (smoke entering from cooker to the Kang) is too high, but the temperature of Kang surface far from the smoke inlet is too low. When the fire is off, the Kang surface temperature will not drop immediately, it will slow down to a certain temperature instead because of the Kang thermal storage. Under certain conditions, the Kang surface temperature and the percentage of heat amount transferred to the room from the Kang will gradually changed with the size of the smoke inlet, and the Kang surface temperature will drop much more slowly after the fire ceased, which will improve the thermal comfort of a Kang.

Dust particles include mold spores or excrement and corpses of the mite and so on. There is a high possibility of allergic reactions in child whose breathing zone is near the floor. Ventilation is one of the best ways to remove dust particles. It is important to know the removal efficiency of dust particles in different ventilation strategies room. In this study, two kinds of ventilation strategies were considered, namely ceiling exhaust and slit exhaust. In the experiments, comparison of the number of particle shows that the ceiling exhaust was a little higher than the slit exhaust. Computational fluid dynamics (CFD) simulations concerning diffusion fields completed. In the simulations, the removal efficiencies of ceiling exhaust and slit exhaust were found 81.5 and 85.8 %, respectively. From the data we concluded that slit exhaust ventilation strategy will produce less dust particles comparing with ceiling exhaust ventilation strategy in room.

District cooling technology is advantageous in warm and hot climatic regions, in that chilled water from a central refrigeration plant is delivered through a distribution network to groups of buildings in an urban district. At a central refrigeration plant, chilled water is generated and supplied to a district to support the air-conditioning systems in buildings. Because of the large scale production, the chiller plant is higher in efficiency than those in individual buildings. Therefore, district-cooling system (DCS) has been applied in a number of countries. In the paper, the technical requirements and the cooling scheme options in the context of the urban environment are discussed. A government-commissioned feasibility study of a proposed district cooling site in Chong Qing is then described. The Results indicate that, firstly the technology is most suitable for new urban developments where system design and construction receive much freedom; secondly the areas, which near a river, are ideal sites for the application of water-source heat pump technology (WHP) to provide district cooling and heating; lastly a large number of benefits, such as economic benefit and environment economic, will be obtained in this project.

At present, exhaust flue gas temperature of coal-fired boiler is generally above 120 °C, while the temperature of boiler burning high sulfur coal may be higher in China. Meanwhile, the boiler burns large amount of fuel to heat the heating network return water to the supply temperature. A specially designed waste heat recovery system, which can reduce exhaust flue gas temperature to 60–70 °C and recycle large amount of sensible heat and latent heat in the flue gas to heat the return water, is designed. This paper included three parts. In the first part, the return water temperature duration in the heating season of 99, 64, 29 MW boilers which are three typically used in Harbin are calculated. The feasibility of the system is verified with the results that the return water temperature kept lower than 55 °C for a long period of time. In the second part, the system implementation plan including the material of heat transfer equipment and the choice of heat pump concerned are discussed. The titanium alloy plate heat exchanger and first absorption heat pump are selected. Then thermodynamic and hydraulic calculations of the system are done to determine the amount of flue gas heat recovery, structure of water spray chamber, plate heat exchangers, and absorption heat pump design. In the third part, the dynamic payback periods of waste heat recovery system used in these three boilers are calculated and the results are less than the life cycle of the heat recovery system.

With the passage of time and enhanced insulation in buildings, nonnegligible change may occur in the existing buildings’ thermal performance. Under this circumstance, the original heating system will not guarantee the heat users’ demand. Therefore, it is necessary to re-calibrate the thermal characteristics of the building, based on which the users’ supply and return water temperature should be determined. In this paper, a model to solve the heat users’ real heat load was established based on energy balance equation, considering that the building’s heat load was uncertain. A correction coefficient β was introduced to illustrate the relationship between the design heat load and the real heat load. A demonstration project in Harbin was tested during the period from January 27, 2011 to February 25, 2011 with the application of this adjustment method to verify the validity of this model. The results showed that the users’ actual room temperature deviated from the design room temperature seriously before the adjustment method used and this deviation was reduced after this method used.

This paper firstly discusses two different operation modes of the split evaporative air conditioner combined evaporative cooling with semiconductor refrigeration technology. Then the sizes of water flow which is required by the outdoor unit are deduced and calculated in two modes of operation. The design step and selection calculation of the split evaporative air conditioner are given in Xi’an region under 2,500 W sensible heat load. For purpose, it lays the foundation for future design and development of the split evaporative air conditioner.

Heating and domestic hot water consume a large amount of energy. The heat supply systems based on fossil fuel burning are of low energy efficiency as well as high air pollution. Air source electricity heat pump (ASAHP) was analyzed to be energy-saving for heating in cold regions. In order to select suitable system for different areas, the primary energy efficiency of electricity heating, coal boiler, gas boiler, electrical heat pump, and ASAHP-driven by various heat sources are compared. Combing the weather characteristics in different areas, the applicability of different systems in China are investigated in the energy efficiency point of view. Results show that the primary energy efficiency of ASAHP is generally higher than that of ASEHP except when the air temperature is very high. Both ASEHP and ASAHP are efficient in the hot summer and warm winter area for domestic hot water. And direct gas-fired ASAHP is the best choice in hot summer and cold winter area, temperate area, cold area as well as severe cold area. Additionally, hot water-driven ASAHP using gas boiler is the second choice for heating in hot summer/cold winter area and temperate area, and for both heating and domestic hot water in cold and severe cold areas. This work is to explore the most suitable heat supply systems for different regions, and is expected to make contributions to building energy saving and emission reduction.

Liquid desiccant system is more and more popular in the air-conditioning system. This paper focuses on the match property analyses of the internally-cooled liquid desiccant system. The unmatched coefficients both of the sensible heat transfer process between the desiccant and the cooling medium and the coupled heat and mass transfer process between the desiccant and the air were defined for the internally-cooled device. Numerical model of the dehumidifier was established for calculating the unmatched coefficients. Match properties of different kinds of liquid desiccant systems under various boundary conditions were then compared. The results show that the internally-cooled device has much smaller unmatched coefficients compared to the two-flow devices (adiabatic dehumidifier and sensible heat exchanger). The unmatched coefficients are good indicators for system improvement with identical heat and mass transfer area.

The frost on the heat exchanger of the air-source heat pump has a great influence of the operating performance. The frosting experiment based on a cascade type air-source heat pump water heater is carried out in the enthalpy-difference in this paper, and the outdoor evaporator of the unit is a finned-tube heat exchanger. In addition, the outdoor environmental conditions include that the outdoor temperature is from −18 to 6 °C and outdoor relative humidity is from 70 to 90 % in this experiment. Experimental results are described below. First of all, the amount of frosting almost changes linearly with the frosting time which is of maximum in this outdoor temperature range of −3 to 3 °C, and the lower outdoor temperature, the more frosting amount; Second, the outdoor relative humidity has a great influence of the quantity, and the more humidity, the more frosting quantity. Finally, the frosting factor is from 6.51 to 10.31 kg/(m

2

·°C·min) and the average value is 8.58 × 10

−4

kg/(m

2

·°C·min), based on the relationships of the area and form of evaporator coil, the time of frosting, the difference of the dew point temperature, and the temperature on the evaporator coil and the frosting quantity.

Many papers have already done performance study in different types of AC systems on R32 and got a series of conclusions. But research papers on the discharge temperature are scarce. Discharge temperature is one of the important indicators of system security. High discharge temperature will cause the compressor lubricant carbonation, wire protection layer aging and has a severe impact on system security after long running. This paper first does comparison of discharge temperature difference between R32 and R410a in commonly used evaporation and condensation temperature range, then predicts the discharge temperature of air conditioning system with R32 through simulation with lumped models. The results show that the discharge temperature of R32 is higher than R410a’s and the lower–upper limit value range is about 0 ~ 35.4 °C under the same evaporation and condensation temperature. It is found that the model predictions for the discharge temperature showed about deviations of ±10 % compared with actual test data.

An experimental study of heat transfer was conducted on rectangular finned heat exchanger with 8-row tubes and wind tunnel system. And compared with four different empirical correlation calculate the heat transfer coefficient of finned tube heat exchanger, Then compared with two different empirical correlation calculate the drag coefficient of finned tube heat exchanger. As can be seen from the result of fitting formula, the total heat transfer coefficient increased as Reynolds number. Finally, the result was fitted into formula of heat transfer coefficient and drag coefficient, which was applicable to a certain velocity range of the same type of tube bundle. Results show that, within the range of wind velocity, both the total heat transfer coefficient and flow resistance were increased as Reynolds number. And it can be concluded the outside tube heat transfer coefficient based on exterior area of bare tube increased obviously as Reynolds number, while that of finned tube increased not obviously as Reynolds number.

The extensive application of ground-coupled heat pump system (GCHP) is restricted by the installation of conventional borehole ground heat exchangers (GHE). Combining the GHE and building foundation piles as “energy piles” can eliminate the drilling cost and land area requirement of a conventional borehole GHE. In this study, the accurate analytical thermal analysis is carried out for simulating the heat transfer process of the novel pile GHE with spiral coils. The temperature responses of the coil pipe wall and the circulating water entering/effusing the pile GHE to the short time step heat transfer loads are deduced based on the established analytical transient three-dimensional spiral source model. Then the operation performance as well as the heat exchange capacity of novel pile GHE is investigated and compared with conventional borehole GHE. The analytical solutions developed in this study can provide an appropriate and convenient tool for thermal analysis and design of the novel foundation pile GHE with spiral coils. It is believed to be a new contribution in the foundation pile GHE field.

Two control methods are presented for the ground source heat pump (GSHP) and radiant floor (RF) heating system, one is the set return water temperature control method, and another one is the set indoor air temperature control method. To search for performance differences of the combined system mentioned above, some experimental exploration is carried out mainly in four aspects: the performance of ground heat exchanger, soil temperature distribution at different depths, the load trace damping during shutdown of the system, and the system energy consumption. Experiment results show that the set indoor air temperature control method gives a better performance in heat exchange ability and system energy consumption when compared with the set return water temperature control method. Both of them have an excellent performance in soil temperature distribution and load trace damping.

For the buildings located in northern areas of china, which belong to the cold climate, their heating loads always larger than the cooling loads in 1 year. When the ground-coupled heat pump (GCHP) systems are utilized in these so-called “heating load dominated” buildings, the unbalance between the heat released into ground in summer and the heat extracted from ground in winter will result in the performance degradation of the GCHP systems year-by-year. In order to ensure the high heating efficiency of the GCHP system used in heating load dominated buildings, it is important to storage the heat into ground to achieve its heat balance. This paper proposes a new type of concrete pavement heat storage system combined with the GCHP system for buildings located in cold climate areas. The operating principle as well as heat transfer mechanism of pavement heat storage system is introduced, the heating capacity of pavement heat storage system is calculated and compared with residential building’s heating load. Based on simulation results, the feasibility of utilizing the concrete pavement as a seasonal heat storage device for the GCHP system is analyzed.

Data center is developing quickly in China, which consumes much operating energy due to the 24 h operating annually. The energy consumption of air-conditioning (AC) system accounts for 40–50 % of the entire energy consumption in data center. There is large energy saving potential since the AC system operate annually even the outdoor environment is cold enough. The indoor thermal environment and energy utilization of a data center in Shanxi Province before and after retrofitting are tested during the July of 2012. The area of data center is 550 m

2

and there are 145 cabinets. In the original design, eight typical air-cooled CRACs (computer room air conditioner) with total cooling capacity of 600 kW provide the required indoor climate. The original AC systems cannot meet the heat dissipation demand of all the cabinets, due to the reason that 14 cabinets with rather higher heat production of 3–8 kW. The total heat production of the 14 cabinets were accounting for 1/5 total heat production of the data center. The measured outlet temperatures of the 14 cabinets were over 30 °C. The retrofitting is focus on the aforementioned 14 cabinets, using separate heat pipe systems in the back-plane of cabinets which are accompanied by water chiller outdoor as cold source. The on-site measurements show that the retrofit separate heat pipe air-conditioning systems can meet the temperature requirement of safety operation of the high-density cabinet. The COP of AC system can reach 2.7. The entire energy consumption of AC systems after the retrofitting can reduce 18 % energy consumption in summer.

The electrostatic cyclone dust collector is a new combination of mechanism and advantages of both electrostatic and cyclone dust collectors, with several advantages of simple structure, low operating cost and high separation efficiency. The article embarks on the basic theory of electrostatics and cyclone dust collector. The charge process on particle is described. Then this paper elaborates upon the research on dust removal mechanism and particle movement regularity in the electrostatic cyclone dust collector based on predecessors’ studies. Finally, the new model for the separation efficiency of electrostatic cyclone dust collector is deduced. The new gas–solid separation theory of cyclone with impulse excitation can provide a theoretical basis for developing a new separator and improving the quality of the separator equipment.

In order to estimate the impact of groundwater advection and axial heat conduction on the performance of borehole heat exchangers in ground source heat pump systems, results obtained from different heat transfer models of a vertical borehole heat exchanger based on line source theory were compared. It is found that the analytical solution from the moving finite line source (MFLS) model reveals the fact that soil temperature field around the borehole migrates along the ground-water advection direction and more obvious variation of the vertical temperature change occurring near the ground surface and the borehole bottom. It means the MFLS model can be used when groundwater advection presents. The results are also validated by 3-D numerical simulation. In addition, the influence of groundwater advection on the soil temperature responses is also analyzed. A larger advection velocity causes the soil temperature to change faster and to achieve a lower stable temperature change as time elapses.

Introduces some principles and calculating method used for the problem of porous brick wall in new energy-saving area. Finite volume method is adopted to complete the numerical analysis of building blocks model. The SIMPLE algorithm is used to solve the equation of speed and pressure. Convection–diffusion subject uses second-order upwind format. Calculation mesh adopts the unstructured hexahedral style. A few examples calculated are given. The date comparisons between calculation and experiment are given up. Rectangular hole brick is affected more stronger than circle hole brick. The wall heat flux and wall temperature have been calculated. Thermal performance can be obtained through numerical calculation in the steady heat transfer, being very approximate from the experimental result. According to the calculation of temperature distribution in the brick, thermal performance can be successfully analyzed.

The research of heat pump mainly focus on experimental research which emphasizes the determination of heat transfer per unit depth, system COP, reasonable buried pipe spacing, soil thermal physical property and so on, but there has been no breakthrough in the aspect of how to ensure the reliability of the system during a long runtime. This paper first heat exchanger, heat pump, the mathematical pump and buildings was modeled and integrated by the mean of connection condition. The optimized method of the heat exchanger was puts forward. The drill hole depth and drilling hole number are taken as optimization variables, the inlet temperature as objective function. Through a case study, the tradition calculation and optimized drill length was compared. The result shows the optimized design method can decreased drill length and number.

Groundwater source heat pump (GWSHP) as a promising renewable energy utilization technology has been widely used in building heating and cooling. But heat breakthrough and groundwater injection have become gradually revealed engineering problems in groundwater heat utilization process. Testing evaluation is an important means to understand the reliability of the practical application of GWSHP. This paper took a residential use of GWSHP system in Yangling Normal Community as study object, focusing on the analysis of “heat breakthrough,” briefly illustrating the groundwater injection. Collected a year’s operating data, mainly including pumping and injection wells water temperature, supply and return water temperature of water source heat pump unit’s evaporator/condenser and outdoor air temperature in winter and summer. The relationship between groundwater temperature repair and heat breakthrough and injection rate were obtained through analyzing the operation test data. These operating parameters are all in the safe operation range of heat pump unit. The results show that heat transport between production water well and injection water well is not significant, and the groundwater temperature restoration is suitable, thus the GWSHP system runs normally and meets the requirement of reliability for residential building air-conditioning application in Yangling Normal Community.

This paper studied the effect of the combined operating of radiant floor and fresh air coil in field experiment according to different ways of cold or hot water supply. By compared and analyzed the differences, which among indoor air temperature/humidity, radiation asymmetry, and thermal comfort in three ways of single, series, and parallel of radiant floor and fresh air coil for cold or hot water. On the basis of the analysis, this paper also discussed the risk of condensation on the surface of the floor. Experimental results showed that the indoor thermal comfort is best and the risk of floor surface condensation is least in series mode.

To propose solar—ground source heat pump and heating network complementary form of heating system, select the baseline of building in cold regions, we use Dest software for dynamic load simulation system to determine the different heating period of operating mode, according to the heating relative load ratio during the entire heating season. Taking TRNSYS transient simulation software as the platform, the complementary heating systems simulation model is established to determine the best ratio of the energy of the complementary heating system. For the benchmark construction of the cold regions, the longest time from 20 to 70 % of the design load, accounting for 63 % of the total heating time, but the time of maximum is only 1 h, and average load accounts for 25.14 % of the design load; solar energy heat can reach 89.61 % of the entire heating season and the dynamic shortest payback period is 8.77 years; solar energy as a complement thermal systems, unit air conditioning area corresponds to the collector area is 0.045 m

2

, the water temperature can reach 50 °C, get the maximum cost to the present value at the same time and the economic effect is the best.

As one of the pilot cities who apply and disseminate with the renewable energy that the National Ministry of Construction has determined, Shenyang has summarized some experiences about the application and promotion of the ground source heat pump (GSHP) technology which is named “Shenyang model,” and constantly expands this application model. Given this understanding, Shenyang fully extend the GSHP that apply the secondary discharge water of urban sewage plant as renewable source, and the circulating cooling water GSHP system using the waste heat of the thermal power plant, soil source heat pump system, the hybrid water source heat pump units working with the central heating system, and the other effective models. All of these systems play an important role in energy conservation and emissions reduction of our city, and also in improving the urban environment.

Ceiling radiant cooling panels (CRCP) system is more comfortable and energy-saving than the traditional convection air-conditioning system according to the research of pioneers. The former research was concentrated in the feasibility, thermal comfort, and energy saving of the CRCP system. Changes of the system parameters are not described systematically under unsteady state. There are hardly any complete and credible reference materials for engineers to design CRCP system of buildings. In this paper, the radiant thermal performance was studied in the experimental platform, and the operating data of the CRCP system was collected in the startup phase and regulating phase of the platform. The results shows that the thermal inertia of the metal radiant panel is small and the response of thermal parameters is very fast under unsteady state in the experiment. The distribution of the surface temperature is uniform on the cool ceiling, and the heat transfer resistances are basically the same among different cooling panels. Learning the changing rules of the CRCP system would provide the engineers reference materials for running control, design, and assessment of the system in the future.

This paper is focused on the classification filtration performance of Polysulfonamide (PSA)/needle-punched PSA filter material at room temperature. And all the experiments are handled based on the test equipment of filter materials’ static characteristics. A four-level and three-factor orthogonal table was adopted in the experiment scheme and the experiment data were processed by dimensional analysis and multiple nonlinear regression method with Statistical Product and Service Solutions (SPSS). It suggests the Regression equation that analyzes the relation between classification filtration efficiency and experimental factors (like average particle diameter, dust load, filtration velocity). And the classification efficiency of the PSA/needle-punched PSA filter material varies apparently with the ranges of particle size.

Based on the Thermodynamic theorem of corresponding states, the relationship between condensation pressure and temperature of subcritical heat pump systems using CO

2

/R600 or CO

2

/R600a as the working fluid is proposed. With the proposed correlation, the effective mass fraction range of component R600 or R600a can be readily determined according to the designed condensation pressure. Or if the condensation temperature is given, it is convenient to get the effective mass fraction scope of R600 or R600a. Within the condensation pressure range of 4.00–7.38 MPa, 36 points are calculated by the fitting formula and then checked by REFPROP8.0. The mean deviation between the fitting relationship and REFPROP8.0, below 1 %, shows that the proposed relationship can be used with satisfactory certainty under the given conditions. The research results may provide a beneficial basic data to promote the application of medium temperature heat pumps using blends of CO

2

with butane and isobutane.

Energy and exergy analyses models were established to evaluate the performance of a ground source heat pump (GSHP) based on the energy conservation and the exergy destruction principles. The GSHP supplies cooling water and hot water to the air handling unit of a building air-conditioning system in cooling and heating season, respectively. It rejects and absorbs heat from the soil through borehole heat exchangers accordingly. The models were programmed and the properties of the working mediums were calculated by calling the software REFPROP. Results indicate that GSHP system operates at higher exergy efficiency in heating mode. The exergy efficiencies of the whole system are 23.07 and 34.31 % in cooling and heating modes, respectively. And the performances of every component are evaluated.

An experimental study concerning frozen water droplets adhered to cold surface subjected to 20 kHz ultrasonic vibration was conducted. The transient process of frozen water droplet shedding from cold surface was recorded and the simultaneous internal temperature variation of cold plate was measured. In addition, the mechanism of ultrasonic vibration for removing frozen water droplets from cold surface was qualitatively analyzed. It is found that the frozen water droplets instantaneously fall off from the vertical surface accompanying with flick phenomenon due to the combined action of interface transverse shear force induced by ultrasonic mechanical effect and impact force generated by ultrasonic cavitation. Meanwhile, an instantaneous internal temperature jump of cold flat occurs. The results indicated that the high frequency ultrasonic vibration can effectively remove the frozen water droplets adhered to cold surface which is the base for frost growth and thus it is a highly effective defrosting method.

The filler is the important heat and mass transfer components of dehumidifier and regenerator in liquid desiccant system. The traditional gas–liquid direct contact filler meets an unfavorable factor which is gas with liquid. In this paper, a new indirect gas–liquid contact partitions filler, which has a specific surface area of 286 m

2

/m

3

and a porosity of 0.86, is proposed. Both regeneration performance of the partitions filler and 5090 wet curtain has been tested on a cross-flow regeneration module laboratory. LiBr solution has been used as the desiccant and the regeneration effect is described by regeneration rate, renewable efficiency, average mass transfer coefficient, and volumetric mass transfer coefficient. The influence of the regeneration performance of the system is analyzed with solution inlet temperature. A regeneration performance comparison of the new filler and the 5090 wet curtain has been carried out. It shows the volumetric mass transfer coefficient of the filler is 7–36 % higher than the 5090 wet curtain one when the solution temperature is between 43 and 60 °C, and the quality of air with liquid of the new filler is 58–87 % lower than the 5090 wet curtain one when the face velocity is between 0.387 and 0.645 m/s.

This dissertation presented simulation and theoretical work on disclosing the coupled relationship of heat and mass transfer between air and desiccant in dehumidifiers. The result shows that the effect of mass transfer process to the heat transfer process is mainly embodied in two aspects: one is the enthalpy carried by the mass flux, another is the water vapor turns into water release of latent heat of vaporization. The effect of heat transfer process to the mass transfer process is mainly embodied in temperature.

In this paper, the floor heat storage in the preheating period and the heat release in the intermittent period are studied during an Intermittent in-slab floor Heating process. The influence of design and operating parameter which are space between pipes, thickness of the filling layer, and pipe water temperature on the floor heat storage and heat release are obtained by using numerical simulation techniques. The relationship between intermittent time and preheating time is also obtained. The research results show that the biggest effect on the preheating time is the space between pipes in the preheating time. In the intermittent period, 2 h later, the two-dimensional heat transfer process can be considered as one-dimensional vertical heat transfer process, and the thickness of the filling layer has relatively big effect on the heat release time.