Investigating Residential HVAC System COP Using Different Engineering Designs – Experimental Study

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Alkarmi, Samer
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جامعة النجاح الوطنية
Palestine suffers from a shortage of electricity because of the Israeli occupation and the lack of resources. This crisis is especially evident in the summer, where temperatures and humidity in some areas are getting rise. In order to provide conditions of comfort, people resort to the use of residential air conditioners increasingly. The statistics show that there is a significant increase in consumption of electricity in the summer due to the use of air conditioners. This leads to interruptions in the supply of electricity. The main reason for excessive power consumption in residential air conditioners is due to the high external temperature. Where the air conditioner operates in higher thermal conditions than that designed to operate on it, which leads to a reduction in the efficiency of the air conditioner. To solve the problem of excessive consumption of electricity in the residential air conditioners, engineering modifications were made to the mechanical circuit of the air conditioner. For this practical experiment, the work steps were divided into three stages: In the first stage, the original air conditioner was tested without any modification. In the second stage, the capillary tube was replaced with a thermal expansion valve, and finally, in the third stage, the surface of the external heat exchanger was reduced with a thermal expansion valve. In the previous three cases the air conditioner was operated under external temperatures ranging from (30℃ - 55℃) and the required readings were recorded. Then performing the necessary calculations to find coefficient of performance (COP) and energy consumption. By comparing the results in the three cases, the following results are shown: The COP of the air conditioner is not affected by the increase in the external temperature when replacing the capillary tube with the thermal expansion valve while maintaining the area of the thermal exchange surface of the external heat exchanger (condenser). the coefficient performance of the air conditioner increased from 3.43 at 30°C ambient temperature to 3.99 at modified air conditioner. At 55°C ambient temperature, the coefficient of performance raised from 2.25 in the case of the original (base) air conditioner to 3.62 in the case of the modified air conditioner. Significant decrease in the consumption of electrical energy when using the thermal expansion valve compared to the condition of the original air conditioner and reduction in harmful emissions of CO2 by 352 kg for 3 months