Effect of Air Flow Obstruction in a Condensing Unit on Split Air Conditioner Performance

Abstract

Obstructions of air flow in the outdoor unit could block the condenser air flow and reduce its heat rejection As a result, it could decrease the performance of a room air conditioning system. The paper presents the effects of the air flow obstruction of a condensing unit on the performance of a split-type air conditioner with refrigerant R410A. The study was conducted experimentally by employing front and side obstructions with varied distance from the condensing unit. The front obstruction of 100 cm height was applied at varied distance from 10 cm to 100 cm, while the side obstruction of the same height was applied at distance of 5, 10, and 15 cm. The presence of air flow obstructions results in the decrease of cooling capacity and coefficient of performance (COP). On the other hand, it increases the input power of the AC unit. From the experiment, it is obvious that the distance of front obstruction of 10 cm results in the reduction of cooling capacity by 46% and COP by 56%. It is also revealed that the distance of the front obstruction of 50 cm or more has no significant effect for the performance of the air conditioning unit. In addition, the side obstructions have the less significant effect than that of the front obstruction.

Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

“…As a comparison, it was reported that obstruction of the air flow in the front and side of condenser gives an increase of power consumption by 2.4% for each 1℃ of increase of condensing temperature [6]. Kumbhar et al [20], whereas, informed that each 1℃ increase of condensing temperature gives an increase of input power by 1.7% based on their experiment using water chiller.…”

“…The mass flow rate of the supply air can be expressed by using the multiplication of air flow rate (Q) and air density (), or ṁ=Qρ (6) In Eq. ( 6), the volumetric flow rate is expressed in m 3 /s while the air density is expressed in kg/m 3 .…”

“…The presence of obstruction in the outdoor unit could also reduce the performance of air conditioner. A reduction of cooling capacity by about 46% and increase of power consumption by 31% were reported when an air-cooled condenser was subjected by an obstruction located in the front of condenser at a distance of 10 cm [6]. It was also informed that at distances of 50 cm or more, the obstruction has no significant effect on the performance of the air conditioner.…”

Performance of Split-type Air Conditioner under Varied Outdoor Air Temperature at Constant Relative Humidity

“…The increase of condensing temperature could also be caused by the reduction of air flow in the condenser caused by air blockage. An increase of energy consumption by 36% and decrease of cooling capacity by 46% were reported when an obstacle is installed in the front of condenser at a distance of 10 cm [9]. The effect of the obstacle decreases with the increase of the distance between the condenser and the obstacle.…”

Evaluation of Split-Type Air Conditioner Performance under Constant Outdoor Moisture Content and Varied Dry-Bulb Temperature

“…This study also noted that the power consumption increased by 10.2%, while the capacity and energy efficiency reduced by 7.9% and 16.5%, respectively. Similar to the high outdoor air DBT, the presence of condenser obstruction decreases the capacity and COP of an air conditioner [26]. The effect has been experimentally investigated by installing airflow barriers in front and side of condenser.…”