Preface
Investigation of combined cooling, heating, and power (CCHP) systems by different researchers in the last decade have revealed that CCHP is reliable and economical. It saves fuel and reduces air pollution and greenhouse gases. It is also safer with respect to centralized power generation systems in critical situations such as war, terrorist attacks, and natural disasters. Due to these essential characteristics it is predicted that the use of distributed power generation such as CHP and CCHP systems will develop rapidly in the near future.
This book is written as a guide for CCHP researchers, designers and operators. The contents of this book can accelerate the new research and save considerable time for those who are new to this topic. This book also presents some general guidelines for operation and maintenance of CCHP systems.
In Chapter 1 most of the published research from 2002 to 2013 is summarized. The main attention of this literature review is to present the main design and decision-making criteria that concern researchers and designers. In addition different CCHP cycles presented by different investigations are discussed and presented. Through this literature review, the reader will become familiar with many CCHP cycles and their components.
In Chapter 2 the main technologies used in the basic CCHP cycles are introduced. These technologies include different prime mover types such as steam turbines, gas turbines, reciprocating internal combustion engines, micro-gas turbines, micro-steam turbines, Stirling engines, fuel cells and thermal photovoltaic technology. The basic CCHP cycles that can be designed with different prime movers are also presented. Furthermore, cooling system technologies, especially those that are thermally operated, are presented in this chapter. Thermally activated cooling systems include absorption chillers, adsorption chillers, solid and liquid desiccant dehumidifiers, and ejector refrigeration systems.
In the third chapter the main recommended evaluation criteria for use in the decision-making and design steps are introduced and formulated. The criteria are classified into four main groups: technological, economical, environmental, and miscellaneous. Every criterion is also divided into several subcriteria. For example, the technological subcriteria include fuel saving, exergy efficiency, overall efficiency, operation in partial load, maturity of the technology, recoverable heat quality, user-friendliness of control and regulation, etc. The economical subcriteria include initial capital cost, operation and maintenance cost, net present value, payback period, internal rate of return, net cash flow, etc. The environmental subcriteria may include reduction of air pollution such as CO2, CO, and NOx as well as noise. The miscellaneous subcriteria may include many parameters such as the footprint, ease of maintenance, import and export limitations on CCHP components, lifetime, etc.
In the fourth chapter, two methods are presented for decision-making for certain CCHP components, such as the prime mover, cooling, or heating systems. Decisions are made based on the fuzzy logic, and the grey incidence approach. These methods are called multicriteria decision-making methods. In this chapter, as an example, the prime mover of a CCHP system is chosen among several options for various climates.
To design a CCHP system, load calculation is one of the most important steps. In Chapter 5 different load calculation methods that can be used to design a CCHP system are presented. In addition, the load calculators and websites that can be used for finding necessary weather information are introduced. Also in this chapter the energy demands of a sample building in five different climates are calculated and compared.
In Chapter 6 different design methods for CCHP systems are presented. These methods include the classic maximum rectangle method (MRM); developed MRM; energy management sizing methods including FEL, FTL, and FSL; the thermodynamical sizing method; the thermoeconomical sizing method; the multicriteria sizing function; and the fitness function method. In addition a CCHP system is designed for five sample climates by using different sizing methods and the results and advantages and disadvantages of sizing methods are compared as well. This chapter is especially helpful for designers.
Using renewable energy sources besides fossil fuels in CCHP systems increases the capabilities of this new technology. In the seventh chapter solar heat in particular is studied for use in CCHP systems. A solar collector is coupled with the CCHP cycle and a method is proposed to determine the optimum direction and size of the collector in five climates.
Since usually the surplus heat is wasted in heating systems and basic CCHP cycles in particular, storing the surplus heat for reuse at a later time can increase the advantages of the CCHP system. In Chapter 8 the principals of thermal energy storage (TES) systems are introduced and the CCHP cycle designed in the previous chapters is equipped with the TES system.
Operation and maintenance of CCHP systems is a great job. A proper operation and maintenance program maintains the CCHP cycle in optimum condition, increases its life span and reliability, and decreases maintenance costs. In Chapter 9 the basics of operation and maintenance, pre-commissioning, commissioning, post-commissioning, and troubleshooting of CCHP cycles are presented as a guideline for operators.
Finally in Chapter 10 the mutual benefits of CCHP cycles for consumers and the government are discussed; this positive impact highlights a bright future for CCHP systems.
We believe that CCHP systems can be reliable as an energy conversion equipment because they use fuel energy very efficiently in comparison with the conventional systems for producing cooling, heating, and power. They are also helpful in reducing the risk of global warming. They are safer in critical situations such as war, terrorist attack, and natural disasters such as flood, earthquake, and thunderstorms.
We believe that this book is just an introduction for the decision-making process for CCHP systems and the design, and optimization of them. We appreciate every proposal, correction, question, comment, or criticism on this book with our heart and soul. The readers can write letters about the book to Dr. Masood Ebrahimi, University Of Kurdistan, Kurdistan Province, Iran. In addition they can send email to [email protected] or [email protected].