Experimental Comparison Between CAV Control and CO_2 Ventilation Control Approaches with respect to energy saving of Air Conditioner

摘要

The objective of this study was to investigate the efficiency of the CO_2 control ventilation to enhance energy saving compared with constant air ventilation (CAV) approach of air conditioner. To this end, a small air-conditioner room of 20 square meters was used as the testing room. A carbon dioxide (CO_2) sensor was installed inside to measure indoor air quality while two enthalpy sensors were installed both inside and outside for indoor and outdoor air enthalpies online monitoring. The algorithm of CO_2 control ventilation used is to compare the CO_2 difference between inside and setpoint; when the inside CO_2 concentration is lower than the setpoint, the controller will sent a signal to stop the fresh air intake and exhaust air fans. Measurement was conducted for three indoor temperature set points namely 24, 25 and 26°C. The indoor CO_2 level was set at 900 ppm, 800 ppm, 700 ppm and 600 ppm. The results of measured electrical power consumption showed that CO_2 approach when compared to the CAV approach could save 21.82%, 18.28%, 2.26% and 0.45% and ventilator save 64.19%, 53.4%, 16.8% and 1.26%, for the four CO_2 concentration indoor setpoint considered respectively. Simple mathematical relationships were also derived to estimate the energy saving using the CO_2 control ventilation. This CO_2 control ventilation could be mainly applied for the air condition room of Thailand.