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Md. A. Islam and B. B. Saha
principle and governing equations of a solar energy driven adsorption cooling system will be elaborated. Besides, TEWI assessment procedure will be explained and
compared for both vapour compression and adsorption cooling systems.
Keywords Adsorption cooling · GWP · HFC · Solar thermal energy · TEWI ·
Vapor compression refrigeration
9.1 Introduction
The main objectives behind the invention of cooling systems are to attain thermal
comfort during summer and to preserve various goods (fish, meat, vegetable, and so
forth) that usually rots very fast at ambient conditions (Arora 2010; Islam et al. 2017).
The conventional cooling systems have four major building blocks: evaporator, compressor, condenser and expansion device. A working fluid (namely refrigerant) flows
through these components, change the phase due to pressure variation and removes
heat from a low-temperature source to a relatively higher temperature sink (Wang
2000). Electricity is required to run this cooling system, and the mechanical compressor consumes about 90% of that electricity. Electricity generation sources are mainly
fossil fuel based and release greenhouse gases during electricity production (Rahman and de Castro 1995; Bose 2010; Cherp et al. 2017). Briefly, a cooling system
indirectly contributes to global warming by using electricity. Moreover, refrigerant
leakage is inevitable from joints and seals, mechanical failure or during servicing
(Tassou and Grace 2005; Francis et al. 2016). Previous generation refrigerants such
as ethers, NH 3 , SO 2 have toxicity problem; H 2 O has narrow operating temperature
range; CFCs and HCFCs have ozone depletion potential and high global warming
impact; HCs are unsafe due to their high flammability issue although they have very
low GWP and wider operation range (Calm 2008; Sarbu 2014). The properties of
some refrigerants are shown in Table 9.1. Currently employed refrigerants in the cooling systems are mostly HFCs and have a very high global warming impact. Hence,
the leaked refrigerant contributes directly to global warming. The summation of indirect and direct warming impact, namely, total equivalent warming impact (TEWI) of
the conventional cooling systems are significantly high (Calm 2002; Makhnatch and
Khodabandeh 2014; Davies and Caretta 2004; Kruse 2000). Hence, the adsorption
cooling system is becoming popular, which can be driven by solar thermal energy
or any low-temperature heat source (Saha et al. 2006; Kayal et al. 2016; Thu et al.
2013; El-Sharkawy et al. 2008). Electricity consumption of this system is very low.
Moreover, natural refrigerants can be used as working fluids which have zero or negligible global warming impact (Habib et al. 2014; Kasaeian et al. 2018; Saha et al.
2001). According to history, Faraday discovered the adsorption cooling phenomenon
in 1948. He observed that NH 3 adsorption onto AgCl could produce cooling. G. E.
Hulse proposed an adsorption refrigeration system with silica gel as adsorbent and
SO 2 as the refrigerant in the 1920s (Wang et al. 2014). Nowadays, many renowned
Md. A. Islam and B. B. Saha
principle and governing equations of a solar energy driven adsorption cooling system will be elaborated. Besides, TEWI assessment procedure will be explained and
compared for both vapour compression and adsorption cooling systems.
Keywords Adsorption cooling · GWP · HFC · Solar thermal energy · TEWI ·
Vapor compression refrigeration
9.1 Introduction
The main objectives behind the invention of cooling systems are to attain thermal
comfort during summer and to preserve various goods (fish, meat, vegetable, and so
forth) that usually rots very fast at ambient conditions (Arora 2010; Islam et al. 2017).
The conventional cooling systems have four major building blocks: evaporator, compressor, condenser and expansion device. A working fluid (namely refrigerant) flows
through these components, change the phase due to pressure variation and removes
heat from a low-temperature source to a relatively higher temperature sink (Wang
2000). Electricity is required to run this cooling system, and the mechanical compressor consumes about 90% of that electricity. Electricity generation sources are mainly
fossil fuel based and release greenhouse gases during electricity production (Rahman and de Castro 1995; Bose 2010; Cherp et al. 2017). Briefly, a cooling system
indirectly contributes to global warming by using electricity. Moreover, refrigerant
leakage is inevitable from joints and seals, mechanical failure or during servicing
(Tassou and Grace 2005; Francis et al. 2016). Previous generation refrigerants such
as ethers, NH 3 , SO 2 have toxicity problem; H 2 O has narrow operating temperature
range; CFCs and HCFCs have ozone depletion potential and high global warming
impact; HCs are unsafe due to their high flammability issue although they have very
low GWP and wider operation range (Calm 2008; Sarbu 2014). The properties of
some refrigerants are shown in Table 9.1. Currently employed refrigerants in the cooling systems are mostly HFCs and have a very high global warming impact. Hence,
the leaked refrigerant contributes directly to global warming. The summation of indirect and direct warming impact, namely, total equivalent warming impact (TEWI) of
the conventional cooling systems are significantly high (Calm 2002; Makhnatch and
Khodabandeh 2014; Davies and Caretta 2004; Kruse 2000). Hence, the adsorption
cooling system is becoming popular, which can be driven by solar thermal energy
or any low-temperature heat source (Saha et al. 2006; Kayal et al. 2016; Thu et al.
2013; El-Sharkawy et al. 2008). Electricity consumption of this system is very low.
Moreover, natural refrigerants can be used as working fluids which have zero or negligible global warming impact (Habib et al. 2014; Kasaeian et al. 2018; Saha et al.
2001). According to history, Faraday discovered the adsorption cooling phenomenon
in 1948. He observed that NH 3 adsorption onto AgCl could produce cooling. G. E.
Hulse proposed an adsorption refrigeration system with silica gel as adsorbent and
SO 2 as the refrigerant in the 1920s (Wang et al. 2014). Nowadays, many renowned