What happens when you increase the room temperature by one degree?

Image courtesy starmanseries on Flickr

That degree is a lot more significant than you think.

There has been a lot of interest in recent days about how increasing the room’s temperature actually helps reduce utility bills. Now, utility bills are never any fun. If there are ways to reduce spending on them, I am sure all of us are eager to find out how. For those of us expatriates living in the Gulf countries, the air-conditioning forms a major part of our monthly bill. There is one way to bring the bills down, which is to turn it off, but that’s not a comfortable option. Luckily, there are quite a few ways to reduce spending.

If you are staying in a house with separate split air-conditioner (A/C) units, it is really very easy to save energy. You can do it by simply improving insulation of the house. However, if you have leased the house as most expatriates residing in Gulf countries do, this is not really a likely option.

There is, however, a more cost-effective and easier way of reducing your mounting electricity bills – which is – just raise the temperature of your air-conditioning by one degree. In case of using a split A/C system, you will notice the result immediately, as the A/C unit will run less in typical on/off type of control. When the unit switches off, you can be assured your electricity bill is not growing.

But if you are living in a high-rise, which is very popular in the Gulf countries, the chances are that apart from a magnificent view, the building also has a district cooling system.  These days district cooling has become a very popular way of providing chilled water required for air conditioning of large buildings. If you read any major district cooling operator’s web site, the arguments for this type of cooling are plenty, starting from improved energy efficiency, extended life-time and reduced maintenance with greater availability compared to other methods.

In such a scenario the energy savings impact of your room temperature increase is not necessarily evident. It depends on how the system has been designed and what kind of equipment has been installed.

The essential idea of district cooling is that the central plant is delivering chilled water to the tower to cool it down. Now, if we increase the temperature by one degree, the amount of cooling required is reduced; that way we need less chilled water flow. This means that the system has to be able to store the extra cooling energy to be used later. Also, it is has to be able to circulate cooling water efficiently at a reduced flow.

Water flow reduction in pipeline can be realized by partial closing valves. However, to substantially reduce energy consumption along with reduction of the water flow, it is required to regulate the speed of the circulation pump itself. In a nutshell, depending on the way a water pump is designed, its power required is reducing in cube when the running speed is reduced. So to achieve real electrical energy saving through the increase of room temperature, it is essential to have the so-called variable speed drives installed to control the pump’s running speed.

So, next time you reduce the temperature of your air-conditioning, there is a lot you can think about. Go on, and start saving energy and reducing your bills.

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About the author

Aki Maenpaa

I've been with ABB since 1993 and held a number of roles in motors, drives and power electronics marketing and sales. Currently I am a local division manager based in the Southern Gulf and I'm responsible for ABB's Discrete Motion products and services offering in the UAE, Qatar, Oman, Bahrain and Kuwait.
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