Friday, 18th November, 2016
In a climate like we have in the UK, where we experience reasonably large fluctuations at predictable times, it makes sense to have good, all-year-round temperature control regardless of our environment. We are also increasingly looking at improving the utilisation of our assets, ie. if we have made a capital outlay on an air conditioning system for the office or any work environment, it is not cost-effective to leave it un-used for large chunks of the year. But many people believe that an air conditioning system is for providing cool air only, and that simply isn’t the case; after all, the term ‘air conditioning’ makes no reference to temperature, it just means we are controlling the air to suit the temperature that makes us comfortable at that time. Therefore, if air conditioning is already installed, you can use it as a space heater when necessary.
People ask how a unit that is primarily used to extract hot air and replace it with cold, can then be expected to do the opposite. But it is relatively simple, and it is explained by understanding the principle of a heat pump.
The heat pump explained
A heat pump in simple terms is a device that moves heat from one place to another. This could be as part of an air conditioning system, but equally, the same applies to a refrigerator or freezer; you are removing hot air and replacing it with cold air set to a desired temperature, and this is done by a heat pump.
To create warm air in a room rather than cold air, the process of how the warm air is produced is simply reversed. And again, you have to understand a basic principle to follow how this will work.
How air conditioning works
However big your air conditioning system is – ie. whether it is a small portable system or a centrally-fitted system serving several rooms – the principle of how cool air is produced is the same. This principle is called the Vapour Compression Refrigeration Cycle, but we will explain it in simple terms. Every air conditioning system uses refrigerant chemicals, which flow through a coil and are turned into a gas by warm air that is extracted from a room. As the gas absorbs this heat the reaction produces cold air, which is then blown into the room. This process uses four main components in the system; a compressor, a condenser, an expansion valve and an evaporator.
Creating heat in this same system is simply adapting it to work in reverse, and this is done by using a reversing valve which effectively ensures the flow of refrigerant is in the opposite direction. In many air conditioning systems this is done via switching to a ‘heating mode’, which ensures the hot condenser coils become the cold evaporator coils, and the flow of refrigerant ensures cold air gets pumped outside and warm air gets pumped into the room.
Benefits of using an air conditioning system for heating
There are many benefits to reversing this traditional process of air conditioning as necessary in the colder months. Firstly there are the space benefits of not installing multiple systems for controlling different temperatures. If you have portable air conditioning units, you are not having to use more space heater appliances to provide warmth in the winter. Heat pumps generally use less electricity than traditional space heaters because they are relying on a natural reaction to produce the heat rather than the electricity producing the heat itself. With heat pumps, electricity is used only to power individual components such as the compressor and fans, so they are far more energy efficient. This of course has financial benefits and also reduces your carbon footprint.
On the flipside, there are potentially troublesome factors to consider with using an air conditioning system for heating purposes, however. Of course there are installation costs to an air conditioning system, and even if your system is a portable one, you will still need to provide a vent to outside. Also, even though we are producing heat, condensate will still be produced and will require handling, as the air is still being ‘conditioned’ and hence de-humidified. Finally, if the ambient room temperature is very low, ie. around 7˚C or 45˚F, which is unusual in most domestic or commercial environments, it becomes inefficient to be transferring the heat in this way and it is more cost-effective to use other heating methods.
At Robinsons we have a team of experts who can discuss all your HVAC requirements and can design a system that works for you both when you need heat and when you need cool air. We have qualified professionals who can look at your premises and work out the most cost-effective solutions that remain properly utilised all-year-round, so call us today.Back to News