120
M. Muttakin et al.
as temperature swing. For a typical single stage silica gel—water adsorption chiller,
the temperature of the hot water requires to be 60–80 °C. However, a multistage
adsorption chiller can be operated at a temperature swing of 10 °C (Saha and Kashiwagi 1997). Theoretically, a temperature swing of 2.2 °C can be utilized to drive a
10-stage adsorption chiller (Saha et al. 2007).
In a solar thermal-powered adsorption chiller, heat is obtained primarily from
the solar thermal collectors. However, an auxiliary electrical heater is often used to
maintain the temperature in the hot water tank. This is required as the performance
of the solar thermal collector strongly depends on the environmental condition. It
is obvious that during rainy days, the output from the collector will be significantly
lower when compared to the same during bright sunny days. The poor solar irradiance
in rainy days results in lower absorbed energy by the solar thermal collector, which
in turn reduces its output.
8.3 Model Equations of a Flat Plate Collector
A typical solar thermal system includes solar thermal collectors, water storage tanks
and necessary piping. An adsorption chiller requires a low temperature heat source
to be driven efficiently, and flat plate collectors (FPC) are the most popular solar
thermal collectors considering low temperature application.
8.3.1 Components of an FPC
As can be seen in Fig. 8.2, the major components of a flat plate collector are;
• Glazing: A glazing material is placed on the top of the FPC. Glass is the most
widely used glazing material because of its ability to transmit 90% of the incoming
shortwave solar irradiation while being opaque to longwave radiation emitted
outward by the absorber plate (Duffie and Beckman 1974).
• Absorber plate: The role of an absorber plate is to support the tubes and fins.
In some collectors, it may be integrated with the tubes. The three most important
materials that are used as absorber plates are copper, aluminium and stainless steel.
• Tubes: Tubes provide the path for the flow of heat-transfer fluid from inlet to outlet.
• Header: The header provides the passage for cold water inlet and hot water outlet.
• Insulation: Insulation prevents the loss of heat from the collector through its bottom
and its side.
• Housing: The housing holds all the components as well as protects the system
from moisture, dust etc.
An FPC is a non-concentrating type of solar thermal collector, i.e., its concentration ratio is one. The concentration ratio signifies the amount of transmitted solar
M. Muttakin et al.
as temperature swing. For a typical single stage silica gel—water adsorption chiller,
the temperature of the hot water requires to be 60–80 °C. However, a multistage
adsorption chiller can be operated at a temperature swing of 10 °C (Saha and Kashiwagi 1997). Theoretically, a temperature swing of 2.2 °C can be utilized to drive a
10-stage adsorption chiller (Saha et al. 2007).
In a solar thermal-powered adsorption chiller, heat is obtained primarily from
the solar thermal collectors. However, an auxiliary electrical heater is often used to
maintain the temperature in the hot water tank. This is required as the performance
of the solar thermal collector strongly depends on the environmental condition. It
is obvious that during rainy days, the output from the collector will be significantly
lower when compared to the same during bright sunny days. The poor solar irradiance
in rainy days results in lower absorbed energy by the solar thermal collector, which
in turn reduces its output.
8.3 Model Equations of a Flat Plate Collector
A typical solar thermal system includes solar thermal collectors, water storage tanks
and necessary piping. An adsorption chiller requires a low temperature heat source
to be driven efficiently, and flat plate collectors (FPC) are the most popular solar
thermal collectors considering low temperature application.
8.3.1 Components of an FPC
As can be seen in Fig. 8.2, the major components of a flat plate collector are;
• Glazing: A glazing material is placed on the top of the FPC. Glass is the most
widely used glazing material because of its ability to transmit 90% of the incoming
shortwave solar irradiation while being opaque to longwave radiation emitted
outward by the absorber plate (Duffie and Beckman 1974).
• Absorber plate: The role of an absorber plate is to support the tubes and fins.
In some collectors, it may be integrated with the tubes. The three most important
materials that are used as absorber plates are copper, aluminium and stainless steel.
• Tubes: Tubes provide the path for the flow of heat-transfer fluid from inlet to outlet.
• Header: The header provides the passage for cold water inlet and hot water outlet.
• Insulation: Insulation prevents the loss of heat from the collector through its bottom
and its side.
• Housing: The housing holds all the components as well as protects the system
from moisture, dust etc.
An FPC is a non-concentrating type of solar thermal collector, i.e., its concentration ratio is one. The concentration ratio signifies the amount of transmitted solar