Hierarchical Gas-Gas Systems

Hierarchical systems (Figs. 2.​3, 2.​4, 3.​1, 3.​2 and 3.​3) are multi-level, clockwise or anticlockwise systems. The clockwise systems include heat engines, while the anticlockwise—heat and power machines. The basic property of hierarchical systems is the fact that heat from an external heat source is input only for one cycle. For an engine it is the cycle superior in hierarchy, i.e. the cycle operating at the highest temperature range, while for a heat and power machine, chiller or heat exchanger it is the lowest cycle in the hierarchy, i.e. the cycle operating at the lowest temperature range. For each remaining cycles the input heat is the heat exported from cycles, in the case of engine, in the hierarchy directly above them, while for a heat and power machine, from cycles located directly below them (Figs. 2.​3, 2.​4).

The losses of exergy stream (reducing mechanical power) in the thermodynamic system caused by the increase in entropy for input and output power media taking part in inner thermodynamic processes and increase in entropy of external heat sources contacting them

Analysing costs of electricity and heat production in hierarchical power plants and gas-steam [1] cogeneration plants (also referred to as Combined Cycle Power Plants) turns out that the capital component is a very significant factor of those costs. Investment outlays on a steam part using the Clausius-Rankine cycle consist approx. 40% of the outlays on gas-steam system, when the gas turbine (both gas and steam turbine have here more general meaning and cover proper turbines and all the necessary auxiliary devices) requires only 30% of those outlays. In addition, installation-construction work making up the remaining 30% of outlays, are mainly (over 2/3) outlays on the steam part-related installation. Consequently, unit (per unit of installed electric power) “turnkey” investment outlays on the so-called simple systems, i.e. power plants and combined heat and power plants using only the Joule-Brayton cycle (the so-called Simple Cycle Power Plants) are more than twice lower as compared to the outlays on combined systems and make up approx, 45% of those outlays [2].

Chapter 3 includes the analysis of energy and economic effectiveness of both operation options of the innovative, hierarchical two-cycle gas-gas engine using combined two clockwise Joule-Brayton cycles, high-temperature Joule-Brayton gas turbine cycle and low-temperature Joule-Brayton cycle of the turboexpander.

The chapter includes an economic analysis of unit hydrogen production costs in the water electrolysis process in the system with the gas–gas engine—Fig. 5.1. But not only. For comparative purposes, we present also the values of the cost for all remaining power generation technologies.

Natural hollow spaces in the rock mass (caverns) or underground mining excavations can be used as compressed air storages with which electricity can be stored (a significant problem may be the leakage of these spaces; another well established way of storing electricity is to store it with the energy of potential water in the upper reservoirs of pumped hydroelectric power plants).

Building nuclear power is absolutely necessary for a number of reasons. (1) Nuclear power is a carbon-free source of electricity. It does not emit dust, sulfur compounds, nitrogen and carbon dioxide at all. It is therefore environmentally friendly. (2) Throughout the year it provides consumers with a stable supply of electricity, without which modern civilization could not exist. The annual use of nuclear power plants’ capacity exceeds 8,000 h. Moreover, and what is extremely important, the nuclear fuel: uranium, plutonium and thorium will last for many hundreds of years, while coal and gas resources are depleting at an increasing pace. Moreover, after the introduction of a closed fuel cycle with multiple use of nuclear fuel (the so-called nuclear reprocessing), it will be enough for tens of thousands of years. In addition, there are over 4 billion tons of uranium dissolved in seawater, and its technical extraction is under control. Nuclear fuel will therefore last for billions of years. (3) Long, 60-year, lifetime of nuclear power plants. (4) The cost of electricity from nuclear power plants is relatively low, especially after their depreciation—Fig. 5.​2. (5) Moreover, the cost of nuclear fuel amounts to merely 5% of the annual operating costs of nuclear power plants.