**4. Results and discussion**

The investment costs of the THU v1.2 prototype and conventional air-conditioning system are reported in **Table 3**. The results show that the overall cost of this protect was approximately 84,860 Euros. This cost is because the authors considered the architectural and engineering aspects of both prototypes. Also, it can be observed that the highest value was for the engineering costs at 69.27% of the total investment cost, so that it is suggested that the designer has to pay attention for proposing competitive and viable prototypes.

The improvements of THU v1.1 prototype reduced the total investment cost by 30%. This percentage is directed directly related to the design, manufacture process and size of the prototype. On the other hand, **Table 3** shows that the supply/handing cost represented no more than 18.89% of the investment cost and that the auxiliary cost contributed only 14.54%, as it was expected. The above data indicate that the design plays an important role in engineering aspects. This means that the designer should select appropriate construction materials, the number of Peltier cells and the distribution of each system considering their cost. Also, the results indicate that the conventional v2.0 system is more economically viable than THU v1.2 because the THU system is the first product built in a prefabricated module. This prototype would be more viable if a considerable number of THU systems were manufactured.

Concerning manufacturing process of heating system, it was noted that investment costs are directly influenced by the size and number of Peltier modules, that is, an increase of Peltier modules increases the number of finned heat sinks, so that the investment costs increase. Also, the use of heat pipe sinks increases the investment costs by 30%. Although the heat pipe sinks offer better performance in terms of heat dissipation, the manufacturing process of a finned heat sink is less complicated than that of a heat pipe sink, so that the finned heat sink


and conventional v2.0 system is about 1TR of heating tonnage. To increase the temperature in the room, an increase of Peltier modules is needed. Therefore, it was deduced that the number of Peltier modules have an important impact on the thermal performance of the prototype.

**Figure 5.** The inside temperature of the room in THU v1.2 and conventional v2.0 system, from January 12 (13:30 h) to 13

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The results showed that THU v1.2 had a more stable thermal behaviour than the conventional air-conditioning system, despite variation in the outside temperature, see **Figures 7** and **8**. It

The conducted tests showed that the nominal consumption of the Peltier equipment, with a set point of 22°C, is approximately 0.45 kW, while the conventional v2.0 system has a consumption of 0.15 kW, with a set point of 26°C. This affirms that the THU v1.2 design should improve the physical model of THU v1.2 prototype, and the annual maintenance cost is between 6 and 10% of the total investment cost of the system. Compared with the conventional air-conditioning system,

**Figure 6.** The inside temperature of the room in THU v1.2 and conventional v2.0 system, from January 13 (13:30 h) to 14

can be claimed that the active mechanism may be a key parameter in the efficiency.

(13:30 h) in Pamplona, Spain.

(13:30 h) in Pamplona, Spain.

**Table 3.** Investment costs of the prototypes v2.0 and conventional air-conditioning system.

is more economic. Moreover, it was seen that an increase in insulation level is beneficial in reducing heating demand. In the supply cost can be see that represent no more that 16% of the investment costs. According to the authors' experiences, these costs can be increased or reduced depending on the location of the supplier. Also, **Table 3** shows that the conventional air-conditioning system is more economically viable than THU v1.2, due to the manufacturing cost.

In regard to the operational costs, two 24-h thermal performance tests in January, from 13:30 to 13:30 h, were carried out in both prototypes, see **Figures 5** and **6**. Firstly, it was noted that after 30 min, the internal temperature of the room in the THU v1.2 reached 21°C, while in conventional system it was 26°C. In both tests, it was observed that there was a difference of 5°C in the internal temperature of the room. This means that THU v1.2 prototype could not reach 26°C in the room. It is because the THU v1.2 prototype was designed with 1/4TR of heating tonnage Techno-Economic Analysis of a Peltier Heating Unit System Integrated into Ventilated Façade http://dx.doi.org/10.5772/intechopen.76642 133

**Figure 5.** The inside temperature of the room in THU v1.2 and conventional v2.0 system, from January 12 (13:30 h) to 13 (13:30 h) in Pamplona, Spain.

and conventional v2.0 system is about 1TR of heating tonnage. To increase the temperature in the room, an increase of Peltier modules is needed. Therefore, it was deduced that the number of Peltier modules have an important impact on the thermal performance of the prototype.

The results showed that THU v1.2 had a more stable thermal behaviour than the conventional air-conditioning system, despite variation in the outside temperature, see **Figures 7** and **8**. It can be claimed that the active mechanism may be a key parameter in the efficiency.

The conducted tests showed that the nominal consumption of the Peltier equipment, with a set point of 22°C, is approximately 0.45 kW, while the conventional v2.0 system has a consumption of 0.15 kW, with a set point of 26°C. This affirms that the THU v1.2 design should improve the physical model of THU v1.2 prototype, and the annual maintenance cost is between 6 and 10% of the total investment cost of the system. Compared with the conventional air-conditioning system,

is more economic. Moreover, it was seen that an increase in insulation level is beneficial in reducing heating demand. In the supply cost can be see that represent no more that 16% of the investment costs. According to the authors' experiences, these costs can be increased or reduced depending on the location of the supplier. Also, **Table 3** shows that the conventional air-conditioning system is more economically viable than THU v1.2, due to the manufactur-

**Description Costs (€) Engineering costs 68.88%** -Construction of sills, general electricity networks, water and fibre optic installation 18,115.38


**Supply/handing costs 15.22%**



**Table 3.** Investment costs of the prototypes v2.0 and conventional air-conditioning system.

2523.90

2381.40

1095.96





In regard to the operational costs, two 24-h thermal performance tests in January, from 13:30 to 13:30 h, were carried out in both prototypes, see **Figures 5** and **6**. Firstly, it was noted that after 30 min, the internal temperature of the room in the THU v1.2 reached 21°C, while in conventional system it was 26°C. In both tests, it was observed that there was a difference of 5°C in the internal temperature of the room. This means that THU v1.2 prototype could not reach 26°C in the room. It is because the THU v1.2 prototype was designed with 1/4TR of heating tonnage

ing cost.


132 HVAC System

test modules

(inside and outside)

plasterboard plate



**Figure 6.** The inside temperature of the room in THU v1.2 and conventional v2.0 system, from January 13 (13:30 h) to 14 (13:30 h) in Pamplona, Spain.

**Figure 7.** The variations of solar radiation, wind speed and outside temperature from January 12 (13:30 h) to 13 (13:30 h) in Pamplona, Spain.

THU v1.2 prototype is more economically viable in maintenance, so that the conventional airconditioning system frequently needs maintenance and the replacement of parts.

The indicator associated with COP heat of the conventional air-conditioning system showed that it is in a range of 2.6–3, while the THU v1.2 prototype is between 0.46 and 1.07, as is illustrated in **Figure 9**. Considering the annual experimental data, the COP Carnot in a heating mode for THU v1.2 prototype is between 5 and 18%. Comparing the results of [43], it could be deduced that the conventional air-conditioning system has a COP of 30%. Thus, it can be noted that the conventional air-conditioning system is more efficient than the THU v1.2 prototype.

> Moreover, other tests have been published in [45, 46], where it is seen that the power consumption has higher values in Peltier systems, which is associated with the behaviour of Peltier in relation with the weather. As shown in **Figure 10**, the THU version 1.1 system consumes approximately 1.2 kW of power, while the THU version 1.2 system consumes approximately 1 kW. Therefore, the THU version 1.2 THU system has a great economic advantage on the

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**Figure 9.** Experimental measurement COP of THU v1.2 prototype versus the months.

In summary, the techno-economic analysis gives rise to several interesting ideas for future research, such as the inclusion of photovoltaic panels and batteries in the prototypes, which

The goal of this study was to describe the conceptual design and the operating mode of an innovative thermoelectric heating unit (THU) prototype and compare the thermal performance of a THU prototype with a conventional air-conditioning system. The analysis of investment costs,

THU version 1.1 prototype.

**5. Conclusions**

will create an autonomous and efficient system.

**Figure 10.** Graphic of the TCHU v1.1 with 12 V in heating.

**Figure 8.** The variations of solar radiation, wind speed and outside temperature from January 13 (13:30 h) to 14 (13:30 h) in Pamplona, Spain.

Techno-Economic Analysis of a Peltier Heating Unit System Integrated into Ventilated Façade http://dx.doi.org/10.5772/intechopen.76642 135

**Figure 9.** Experimental measurement COP of THU v1.2 prototype versus the months.

**Figure 10.** Graphic of the TCHU v1.1 with 12 V in heating.

Moreover, other tests have been published in [45, 46], where it is seen that the power consumption has higher values in Peltier systems, which is associated with the behaviour of Peltier in relation with the weather. As shown in **Figure 10**, the THU version 1.1 system consumes approximately 1.2 kW of power, while the THU version 1.2 system consumes approximately 1 kW. Therefore, the THU version 1.2 THU system has a great economic advantage on the THU version 1.1 prototype.

In summary, the techno-economic analysis gives rise to several interesting ideas for future research, such as the inclusion of photovoltaic panels and batteries in the prototypes, which will create an autonomous and efficient system.

#### **5. Conclusions**

THU v1.2 prototype is more economically viable in maintenance, so that the conventional air-

**Figure 7.** The variations of solar radiation, wind speed and outside temperature from January 12 (13:30 h) to 13 (13:30 h)

The indicator associated with COP heat of the conventional air-conditioning system showed that it is in a range of 2.6–3, while the THU v1.2 prototype is between 0.46 and 1.07, as is illustrated in **Figure 9**. Considering the annual experimental data, the COP Carnot in a heating mode for THU v1.2 prototype is between 5 and 18%. Comparing the results of [43], it could be deduced that the conventional air-conditioning system has a COP of 30%. Thus, it can be noted that the conventional air-conditioning system is more efficient than the THU v1.2 prototype.

**Figure 8.** The variations of solar radiation, wind speed and outside temperature from January 13 (13:30 h) to 14 (13:30 h)

in Pamplona, Spain.

in Pamplona, Spain.

134 HVAC System

conditioning system frequently needs maintenance and the replacement of parts.

The goal of this study was to describe the conceptual design and the operating mode of an innovative thermoelectric heating unit (THU) prototype and compare the thermal performance of a THU prototype with a conventional air-conditioning system. The analysis of investment costs, maintenance costs and operational costs was used as a reference point in the comparison. We found that the overall cost of this project was approximately 84,860 Euros.

HVAC heating ventilating and air conditioning

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K total thermal conductance (W/K)

PLC programmable logic controller

S cross-sectional area of semiconductor arms (m)

κ thermal conductivity of the semiconductor materials

l length of the semiconductors (m2)

I load current (A)

PV photovoltaic

q heat dissipated

R resistance (Ω)

m number of Peltier cells

TE-AD thermoelectric air duct TEM thermoelectric modules

TR refrigeration tons

V voltage

Greek letters

Subscripts

V1.1 version 1.1 v1.2 version 1.2

THU thermoelectric heating unit

α total Seebeck coefficient

ρ electrical resistivity

a ambient c cold side

cond conductivity

eva evaporator

n n-type semiconductors p p-type semiconductors

H hot side

By focusing on the investment costs of the THU system, the results reveal that THU v1.2 prototype design is 30% more economical than THU v1.1 design, due to a better design strategy in the manufacture process and the dissipation systems. By considering only dissipation systems, it was noted that the use of heat pipe sinks increase by 30% the investment costs. Although the heat pipe sinks offer better performance in terms of heat dissipation, the manufacturing process of a finned heat sink is less complicated than that of a heat pipe sink, so that the finned heat sink system is more economic.

From a comparative point of view, the results show that the conventional air-conditioning system is economically viable than a THU system; therefore, if THU was to enter the market, it is necessary to implement a strategy that reduces costs. Regarding the thermal performance, the results demonstrate that THU v1.2 had a more stable thermal behaviour than the conventional air-conditioning system. The maintenance costs indicated that THU v1.2 prototype is more economically viable in maintenance than the conventional air-conditioning system. Moreover, verifying the environmental benefits between the studied systems, it was found that the maintenance of a conventional air-conditioning system has a greater environmental impact than the THU v1.2 system. The authors recommended a life cycle analysis (LCA) of both prototypes, in order to know the pros and cons of the environment.
