One of the most dominant questions in our mind when we want to purchase an air conditioner is, what is the right air conditioner to use? This question points not to what brand of air conditioner to buy, but rather what is the cooling capacity required.
To understand the selection of air conditioner, we first have to know the definition of cooling capacity.
Cooling capacity for a room is basically the heat load in a room that we have to remove in order to achieve certain room temperature and humidity. For most design, this temperature is 24oC and 55 percent humidity. Heat load is measure in Btu per hour. 1 Btu per hour is equivalent to the heat energy required to increase 1 pound of water by 1oF.
A compressor with 1 horsepower capacity is able to remove approximately 9000 Btu/hr of heat. To make things easier, it is generally taken that 1 horsepower means 9000 Btu/hr cooling capacity, even though there are some brands which give you higher than that, some as high as 10,000 Btu/hr from a 1 horsepower compressor. The higher the Btu, the higher the cooling capacity.
Heat in a room comes from many sources. From outside, heat comes through windows, roof, floor and walls. The more exposure to the heat source, the greater the heat load will be. Therefore, rooms facing east and west have higher heat load than rooms facing north and south. Even the material of the glass and bricks affect the heat gain.
Internally, the heat sources are the number of people and their activities, electrical appliances, lighting, heat stove and fresh air that flow into the room. Of course, the bigger the room is, the higher the cooling capacity is required.
It is not easy to estimate the actual heat load of a room without going through some tedious calculation. You are advised to consult air conditioner contractors before you decide on the equipment. Bring along the plan and measurement of your room and be specific what is the function of the room, is it a bedroom or a living room?
There is however, a rule of thumb that could give you a rough estimation of the required cooling capacity. This can be achieved by doing a simple calculation.
The formula to calculate estimated cooling capacity:
Total BTU = A + B
= Btu / Hr
A = (Room Width (Feet) x Room Length (Feet) x 50)
B = (No of People x 500)
Faster way to calculate cooling capacity.
The calculation just now is for bedroom only. For other applications, the factor has to be changed. This rule of thumb calculation is just for estimation purposes. It is advised to reconfirm with your air conditioner contractors again before you place your order.
Sources From: www.daikin.com.my