**4. Results**

**Figure 6** shows the behavior of the COP and room and environment temperature for the absorption and adsorption systems during a sunny day (from 2003 to 2016 h). The coefficient of performance is almost keeping constant for ABS (0.71) caused by the short range of operation of THOT (see **Table 2**) and from 0.46 to 0.48 for ADS. The room temperature was kept from 24 to 26°C; when room temperature is lower than 24°C, the control temperature is turned off (night).

**Figure 7** shows the function of the MTV to keep the generator temperature at the maximum range of operation. When the tank temperature (T4, from **Figure 5**) remains on the range of operation, all flow rates go to the tank (m1 = m3 = 1261 kg/h and m2 = 0, from 1476.1 to1476.8 h); however when it is higher than 95°C (from 1477.0 to 1486.8 h), m1 splits into m3 (m3 = m4) and m2 to keep T5 at 95°C, mixing a high temperature coming from stream 4 with stream 2 (T2 = T1).

Next sections will show the condition to operate the cooling system at improved conditions based on the tilt of the solar collector, activation temperature, and storage tank specific volume (SV) [2, 8, 9]. The period of evaluation was from March to May (1460–3560 h) to operate the cooling system due to the highest ambient temperature in a year in Temixco, Mexico [6], as shown in **Figure 8**, besides there are several days with very poor (2190–2300 h) or null beam radiation.

#### **4.1 Selection of the tilt**

**Figure 9** shows the energy from the solar collector as a function of the tilt of the solar collector. 7° obtained the maximum solar collector energy (1.265 × 107 ) during the 3 months evaluated using 30 m2 of area solar collector and a storage tank of 3 m3 .

#### **4.2 Selection of the activation temperature**

**Figures 10** and **11** show the COP as a function of the input generator temperature without and with MTV for absorption and adsorption chiller, respectively.

**95**

**Figure 8.**

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating…*

*DOI: http://dx.doi.org/10.5772/intechopen.84737*

*COP and room and environment temperature behavior within a day.*

*Behavior of temperatures and flow rates of the modulating tempering valve.*

*Environment and beam radiation behavior within 3 months.*

**Figure 6.**

**Figure 7.**

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating… DOI: http://dx.doi.org/10.5772/intechopen.84737*

**Figure 6.**

*Zero and Net Zero Energy*

**Auxiliary Power**

*Parameter supplied to the pumps of the cooling system.*

**3.3 Parameters**

**Table 4.**

**4. Results**

The energetic performance of the cooling systems can be evaluated using two indicators: solar fraction (SF) and heating fraction (HF). Solar and heating fractions are defined as the amount of energy supplied by solar resources (QCOL) and heater system

**(kJ/h)**

Pump (chilled water) 1339 4.19 1789 Coil (Type 3d-2) 1339 1.22 2487 Pump (Type 3d-3, solar collector) 2664 2.34 5442 Pump (Type 3d-4, hot water) 1339 2.34 1261 Pump (Type 3d-5, cooling water) 1339 4.19 4230 Cooling Tower (fan) 2013 — —

**Cp (kJ/kg °C)** **m (kg/h)**

**Figure 6** shows the behavior of the COP and room and environment temperature for the absorption and adsorption systems during a sunny day (from 2003 to 2016 h). The coefficient of performance is almost keeping constant for ABS (0.71) caused by the short range of operation of THOT (see **Table 2**) and from 0.46 to 0.48 for ADS. The room temperature was kept from 24 to 26°C; when room temperature

**Figure 7** shows the function of the MTV to keep the generator temperature at the maximum range of operation. When the tank temperature (T4, from **Figure 5**) remains on the range of operation, all flow rates go to the tank (m1 = m3 = 1261 kg/h and m2 = 0, from 1476.1 to1476.8 h); however when it is higher than 95°C (from 1477.0 to 1486.8 h), m1 splits into m3 (m3 = m4) and m2 to keep T5 at 95°C, mixing a

Next sections will show the condition to operate the cooling system at improved conditions based on the tilt of the solar collector, activation temperature, and storage tank specific volume (SV) [2, 8, 9]. The period of evaluation was from March to May (1460–3560 h) to operate the cooling system due to the highest ambient temperature in a year in Temixco, Mexico [6], as shown in **Figure 8**, besides there

**Figure 9** shows the energy from the solar collector as a function of the tilt of the

**Figures 10** and **11** show the COP as a function of the input generator temperature without and with MTV for absorption and adsorption chiller, respectively.

of area solar collector and a storage tank of 3 m3

) during

.

(QHEATER), respectively, divided by the total energy supplied (QCOL + QHEATER).

is lower than 24°C, the control temperature is turned off (night).

high temperature coming from stream 4 with stream 2 (T2 = T1).

are several days with very poor (2190–2300 h) or null beam radiation.

solar collector. 7° obtained the maximum solar collector energy (1.265 × 107

**94**

**4.1 Selection of the tilt**

the 3 months evaluated using 30 m2

**4.2 Selection of the activation temperature**

*COP and room and environment temperature behavior within a day.*

**Figure 7.** *Behavior of temperatures and flow rates of the modulating tempering valve.*

**Figure 8.** *Environment and beam radiation behavior within 3 months.*

**Figure 9.** *Behavior of the tilt of the solar collector on solar fraction.*

**Figure 10.** *Effect of the activation temperature on the solar fraction absorption system without and with MTV.*

**Figure 11.**

*Effect of the activation temperature on the solar fraction adsorption system without and with MTV.*

A temperature of 111 and 109°C was considered a good option to operate the absorption system without and with MTV. While an input temperature generator of 75°C was considered to operate the adsorption system for without and with MTV, 80°C should be used when the area collector is lower than 60.96 m2 .

**97**

**Figure 13.**

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating…*

The variation of the solar fraction with respect to the specific volume is presented in **Figures 12** and **13** for absorption and adsorption systems, respectively,

good choice for the configuration without and with MTV for absorption system,

tively, for the adsorption system. This represented a 52.2 and 22.7% of reduction for

**Figures 14** and **15** show the heater energy as a function of the storage tank at several solar collector areas for absorption and adsorption chillers, respectively. It can be seen that there is an increment of heater energy when the volume is

to obtain high values of the solar fraction. Besides a certain storage volume value,

more energy is required at higher storage volume. However, when the solar

consumption of energy because the storage tank has a high capacity to keep

**Figures 16** and **17** show the energy of the solar collector (QCOL), heater (QHEATER), and the total energy supplied (WTOTAL) to the electric equipment

were a

was selected

were selected for without and with MTV, respec-

, the increment of volume decreases the

of the solar collector area for both chillers because

**4.3 Selection of the number of solar collectors and storage tank**

at different solar collector areas. These figures show that 35 and 23 l/m<sup>2</sup>

absorption and adsorption systems. A solar collector area of 60.96 m2

the increment of the solar fraction, is not significant [2].

*DOI: http://dx.doi.org/10.5772/intechopen.84737*

respectively, while 27 and 22 l/m2

incremented at 30.48 m<sup>2</sup>

more energy.

**Figure 12.**

collector area is higher than 60.96 m<sup>2</sup>

*Solar fraction against storage-specific volume for absorption chiller.*

*Solar fraction against storage-specific volume for adsorption chiller.*

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating… DOI: http://dx.doi.org/10.5772/intechopen.84737*

#### **4.3 Selection of the number of solar collectors and storage tank**

The variation of the solar fraction with respect to the specific volume is presented in **Figures 12** and **13** for absorption and adsorption systems, respectively, at different solar collector areas. These figures show that 35 and 23 l/m<sup>2</sup> were a good choice for the configuration without and with MTV for absorption system, respectively, while 27 and 22 l/m2 were selected for without and with MTV, respectively, for the adsorption system. This represented a 52.2 and 22.7% of reduction for absorption and adsorption systems. A solar collector area of 60.96 m2 was selected to obtain high values of the solar fraction. Besides a certain storage volume value, the increment of the solar fraction, is not significant [2].

**Figures 14** and **15** show the heater energy as a function of the storage tank at several solar collector areas for absorption and adsorption chillers, respectively. It can be seen that there is an increment of heater energy when the volume is incremented at 30.48 m<sup>2</sup> of the solar collector area for both chillers because more energy is required at higher storage volume. However, when the solar collector area is higher than 60.96 m<sup>2</sup> , the increment of volume decreases the consumption of energy because the storage tank has a high capacity to keep more energy.

**Figures 16** and **17** show the energy of the solar collector (QCOL), heater (QHEATER), and the total energy supplied (WTOTAL) to the electric equipment

**Figure 12.** *Solar fraction against storage-specific volume for absorption chiller.*

**Figure 13.** *Solar fraction against storage-specific volume for adsorption chiller.*

*Zero and Net Zero Energy*

**96**

**Figure 10.**

**Figure 9.**

*Behavior of the tilt of the solar collector on solar fraction.*

**Figure 11.**

A temperature of 111 and 109°C was considered a good option to operate the absorption system without and with MTV. While an input temperature generator of 75°C was considered to operate the adsorption system for without and with MTV,

*Effect of the activation temperature on the solar fraction adsorption system without and with MTV.*

*Effect of the activation temperature on the solar fraction absorption system without and with MTV.*

.

80°C should be used when the area collector is lower than 60.96 m2

(pumps, fans, and heater) as a function of the storage tank volume (ST) at 60.96 m2 of the solar area. The calculated storage tank volume corresponds to 2.13 and 1.40 m3 without and with MTV for absorption system and 1.64 and 1.34 m3 for adsorption system, respectively. The use of storage volume higher than 3 m3 has a soft effect on the QHEATER and WTOTAL for absorption chiller with MTV and adsorption chiller.

**Table 5** shows the values of the parameter showed in **Figures 16** and **17**. It was a little decrement of solar collector energy (from 1.77 × 107 to 1.61 × 107 kJ) with and without MTV for absorption chiller because the time of operation of the solar

**Figure 14.** *Energy consumption of the heater against the storage volume for absorption chiller.*

**Figure 15.** *Energy consumption of the heater against the storage volume for adsorption chiller.*

**99**

**5. Conclusion**

**Figure 17.**

**Table 5.**

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating…*

collector was more using the MTV, then the temperature of the storage tank was higher and this reduces the efficiency of the solar collector, however it was a significant reduction on the QHEATER and WTOTAL for both chillers, mainly for absorption chiller, this represents almost a 54.16 and 33.68%, respectively, while 19.23 and

**m3**

ABS 35 60.96 2.13 1.77 0.74 1.27 ABS, MTV 23 60.96 1.40 1.61 0.48 0.95 ADS 27 60.96 1.64 2.02 0.62 1.69 ADS, MTV 22 60.96 1.34 2.05 0.52 1.44

**QCOL, kJ (1 × 107 )**

**QHEATER, kJ (1 × 107 )**

**WTOTAL, kJ (1 × 107**

**)**

The reduction of the QHEATER is lower for adsorption than absorption chiller because the range of operation of the generator temperature is shorter for absorption than adsorption; however, WTOTAL energy is higher for adsorption chiller than absorption chiller (1.27 kJ for absorption and 1.69 kJ for adsorption without MTV), because it has lower COP (around 0.53) than absorption chiller (around 0.70) and

This chapter presented a thermal analysis of the absorption and adsorption chillers in a dynamic condition for conditioning a building located in Temixco, Mexico, using TRNSYS and Microsoft Excel software from March to May. In this study, both chillers with and without MTV to increase the operation time using evacuated solar

• The maximum solar collector energy was obtained with an angle of tilt of 7°.

• The COP has the higher values when using the input generator temperature. It selected a minimum temperature of working of 111 and 109°C for absorption

collectors were compared. The following conclusions are presented:

chiller without and with MTV, and 75°C for adsorption chiller.

17.36% of reduction was for adsorption chiller.

*Results of the selected conditions for cooling chillers.*

*The energy of the equipment against the storage volume for adsorption chiller.*

**SV, l/m2 ACOL, m2 ST,** 

electric equipment have more time of operation.

*DOI: http://dx.doi.org/10.5772/intechopen.84737*

**Figure 16.**

*The energy of the equipment against the storage volume for absorption chiller.*

*Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating… DOI: http://dx.doi.org/10.5772/intechopen.84737*

**Figure 17.**

*Zero and Net Zero Energy*

**Figure 14.**

**Figure 15.**

(pumps, fans, and heater) as a function of the storage tank volume (ST) at 60.96 m2 of the solar area. The calculated storage tank volume corresponds to 2.13 and 1.40 m3

the QHEATER and WTOTAL for absorption chiller with MTV and adsorption chiller. **Table 5** shows the values of the parameter showed in **Figures 16** and **17**. It was

and without MTV for absorption chiller because the time of operation of the solar

for adsorption

kJ) with

has a soft effect on

to 1.61 × 107

without and with MTV for absorption system and 1.64 and 1.34 m3

system, respectively. The use of storage volume higher than 3 m3

a little decrement of solar collector energy (from 1.77 × 107

*Energy consumption of the heater against the storage volume for absorption chiller.*

*Energy consumption of the heater against the storage volume for adsorption chiller.*

*The energy of the equipment against the storage volume for absorption chiller.*

**98**

**Figure 16.**

*The energy of the equipment against the storage volume for adsorption chiller.*


#### **Table 5.**

*Results of the selected conditions for cooling chillers.*

collector was more using the MTV, then the temperature of the storage tank was higher and this reduces the efficiency of the solar collector, however it was a significant reduction on the QHEATER and WTOTAL for both chillers, mainly for absorption chiller, this represents almost a 54.16 and 33.68%, respectively, while 19.23 and 17.36% of reduction was for adsorption chiller.

The reduction of the QHEATER is lower for adsorption than absorption chiller because the range of operation of the generator temperature is shorter for absorption than adsorption; however, WTOTAL energy is higher for adsorption chiller than absorption chiller (1.27 kJ for absorption and 1.69 kJ for adsorption without MTV), because it has lower COP (around 0.53) than absorption chiller (around 0.70) and electric equipment have more time of operation.

### **5. Conclusion**

This chapter presented a thermal analysis of the absorption and adsorption chillers in a dynamic condition for conditioning a building located in Temixco, Mexico, using TRNSYS and Microsoft Excel software from March to May. In this study, both chillers with and without MTV to increase the operation time using evacuated solar collectors were compared. The following conclusions are presented:

