Effect of Piping Distance on the Energy Consumption of a Split-Unit Air Conditioner
Air conditioning is sometimes necessary to help maintain the required level of thermal comfort in modern buildings. Split-unit air conditioning equipment generally consumes significant amount of electricity for operation. The energy consumed depends on several environmental and technical variables. One important variable is the refrigerant pipe length installation between the indoor and outdoor units. However, information on the extent of how the pipe length affects energy consumption is scanty in literature. This research used a single-phase energy meter to study the energy consumption of a 3500 W cooling capacity split-unit air conditioner for three refrigerant pipe lengths of 3m, 5m and 7m for runtime
of 4 hours. Generally, the energy consumption increased with increasing pipe length. The recorded energy consumptions were 3.54 kWh, 4.29 kWh, and 5.08 kWh for the refrigerant pipe lengths of 3m, 5m, and 7m respectively. Increasing the pipe length from 3m to 5m caused 21.2% increase in energy consumption. Again, increasing the pipe length from 3m to 7m caused 43.5% increase in energy consumption. However, increasing the pipe length from 5m to 7m led to 18.4% increase in energy consumption. These results demonstrate increases in the air conditioning energy consumption with increasing refrigerant pipe length between the indoor and outdoor units, but with a reducing effect as the length gets longer.