9 TEWI Assessment of Conventional and Solar Powered Cooling Systems
153
Expansion
valve
Desorption
bed
Adsorption
bed
Condenser
Evaporator
Liquid
Liquid
+
Vapor
Vapor
Vapor
Hot water in
Hot water out
Cooling water in
Cooling water out
Cooling
tower
Solar
collector
Hot water
reservoir
Ambient
water in
Hot
water
out
V 1
V 2
V 3
V 4
Fig. 9.2 Adsorption cooling system by using solar thermal energy
et al. 2007; Cho and Kim 1992; Bassols-Rheinfelder 1985; Buonomano et al. 2018;
Tangkengsirisin et al. 1998; Al Mers et al. 2006; Chang et al. 2009). Other three
components of the system are the same as VCR. Some additional components are
also required in the solar cooling system for the cooling to happen. The complete
system is entitled as adsorption cooling system (ACS), which is shown in Fig. 9.2.
The main component of an adsorption bed is the adsorbent. An adsorbent material
contains millions of pores and capable of adsorbing (capture and hold) the refrigerant
(also called adsorbate) molecules. Choosing the appropriate adsorbent/adsorbate is
crucial to design an efficient adsorption cooling system.
9.2.2.1 Adsorption/Desorption
Adsorption is the phenomenon to trap and retain refrigerant molecules into the adsorbent pores. Adsorption capacity depends on the porous properties (surface area, pore
width, pore volume) of the adsorbent and also surrounding conditions (temperature
and pressure). Hence, choosing the adsorbent is crucial for a solar cooling system.
Properties of some common adsorbents are shown in Table 9.2.
The refrigerant molecules need to be regenerated and recirculated to complete the
refrigeration cycle. The regeneration process is called desorption. Hot water is passed
through the heat exchanger coil, which is placed inside the adsorption/desorption bed
for the regeneration. Required hot water for the desorption is obtained from solar
thermal energy.
9.2.2.2 Solar Collector
A solar collector is an apparatus that accumulates or concentrates solar insolation.
There are various types of solar collectors such as flat plate collector, parabolic
collector, direct absorption collector, photovoltaic thermal (PVT) collector, hybrid
photovoltaic and thermal collector (Khullar et al. 2012; Phelan et al. 2013; He et al.
153
Expansion
valve
Desorption
bed
Adsorption
bed
Condenser
Evaporator
Liquid
Liquid
+
Vapor
Vapor
Vapor
Hot water in
Hot water out
Cooling water in
Cooling water out
Cooling
tower
Solar
collector
Hot water
reservoir
Ambient
water in
Hot
water
out
V 1
V 2
V 3
V 4
Fig. 9.2 Adsorption cooling system by using solar thermal energy
et al. 2007; Cho and Kim 1992; Bassols-Rheinfelder 1985; Buonomano et al. 2018;
Tangkengsirisin et al. 1998; Al Mers et al. 2006; Chang et al. 2009). Other three
components of the system are the same as VCR. Some additional components are
also required in the solar cooling system for the cooling to happen. The complete
system is entitled as adsorption cooling system (ACS), which is shown in Fig. 9.2.
The main component of an adsorption bed is the adsorbent. An adsorbent material
contains millions of pores and capable of adsorbing (capture and hold) the refrigerant
(also called adsorbate) molecules. Choosing the appropriate adsorbent/adsorbate is
crucial to design an efficient adsorption cooling system.
9.2.2.1 Adsorption/Desorption
Adsorption is the phenomenon to trap and retain refrigerant molecules into the adsorbent pores. Adsorption capacity depends on the porous properties (surface area, pore
width, pore volume) of the adsorbent and also surrounding conditions (temperature
and pressure). Hence, choosing the adsorbent is crucial for a solar cooling system.
Properties of some common adsorbents are shown in Table 9.2.
The refrigerant molecules need to be regenerated and recirculated to complete the
refrigeration cycle. The regeneration process is called desorption. Hot water is passed
through the heat exchanger coil, which is placed inside the adsorption/desorption bed
for the regeneration. Required hot water for the desorption is obtained from solar
thermal energy.
9.2.2.2 Solar Collector
A solar collector is an apparatus that accumulates or concentrates solar insolation.
There are various types of solar collectors such as flat plate collector, parabolic
collector, direct absorption collector, photovoltaic thermal (PVT) collector, hybrid
photovoltaic and thermal collector (Khullar et al. 2012; Phelan et al. 2013; He et al.