**4.4 Environmental evaluation**

To perform the environmental evaluation, the CO2 emissions related to gas and electricity prices are needed, as applied to the UK. Therefore, the values assigned to the parameters in this study are provided [34, 35] including 0.5246 kg CO2 (e)/ kWe h for electricity and 0.1836 kg CO2 (e)/kWth h for gas. Additionally, in the UK, the electricity price at Feed-In Tariff (FIT) and the renewable heat incentive (RHI) are £0.1097/kWh and £0.052/kWh, respectively [36, 37]. Results confirmed from **Figure 12** that the gas burners system produces energy consumption of about 39,851 kWh resulting in about 10.27 tons CO2 emission, while the hybrid renewable heating system has an only energy consumption of 10,978 kWh which is equivalent to 2.026 tons CO2 emission. This indicates that the novel hybrid system could save about 28,873 kWh energy consumption, making for a reduction of total CO2 emission of approximately 8.3 tons. **Table 2** describes the calculation processes of energy consumption, CO2 emission and operating cost of the gas burners and PV/T with heat pump systems.

#### **4.5 Summary**

To sum up, the hybrid renewable energy heating system could save 28,873 kWh of thermal and electrical energy consumption, £1528 of operating

**Figure 12.**

*Comparison of energy consumption and CO2 emission between gas burners and hybrid renewable heating systems.*

*Energy, Economic and Environmental (3E) Assessments on Hybrid Renewable Energy... DOI: http://dx.doi.org/10.5772/intechopen.102025*


**Table 2.**

*Calculation process of energy consumption, CO2 emission and operating cost between gas burners and PV/T with heat pump systems.*

cost with 5.5 years' payback period and 8.3 tons of CO2 emission. Additionally, the electrical output of the PV/T array could achieve approximately 11,867 kWh per annum whereas the thermal energy output is about 30,210 kWh per annum.

According to previous studies [19, 22, 25, 38], it is observed that the hybrid of solar and geothermal energy systems used in a poultry house is rare. Specifically, Fawaz et al. [22] demonstrated that the solar-assisted localized heating system could save approximately 74% of the energy demand and exhibit a 4.6 years of payback period. To improve the chicken meat and eggs production, Gad et al. [19] concluded that the thermal efficiency of the solar heating system is about 71.6% whereas the PV electrical efficiency is 12.5%. Choi et al. [25] designed, constructed and tested a geothermal heat pump system for ameliorating the interior environment of the poultry shed. It is demonstrated that the average interior air temperature could be kept in the range from 24.8 to 32.2°C whereas the relative humidity varies from 45.2 to 72.6%. Moreover, the GHP poultry house could save about 92% of the overall energy expense in comparison with the normal poultry shed. And also, the concentration of CO2 in the GHP poultry house could be decreased by 3299 ppm, by comparison, in the conventional shed, it is decreased by 4945 ppm. Uzodinma et al. [38] assessed the performance of a solar thermal collector with a phase change materials system for poultry incubating chamber, and observed that the temperature of the chamber could be kept in the range from 36 to 39°C, meanwhile, an average egg hatchability could reach 62.37%.

Herein, this proposed hybrid PV/T with heat pump system could allow taking the benefit of high solar irradiation rates and soil heat, thus improving system performance, ameliorating the interior environment of poultry shed and boost meat and eggs production.
