By COLIN REID features@algarveresident.com
Colin Reid is the technical director at the Enova Group and is a chartered engineer specialising in renewable and sustainable energy systems. He has over 20 years experience in the industry and lives with his wife and three children near Almancil.
This month we review the various types of heat pump available and how appropriate they are for the Algarve market.
There is much talk now about Ground Source Heat Pumps, or Geothermal Heat Pumps but it is important to look carefully at how suitable these systems are in the Algarve.
Firstly we need to look at how these systems work. Heat pumps are refrigeration circuits working in reverse. So, for example, in a domestic fridge the circuit moves heat from the fridge compartment and transfers this heat to the air at the back of the fridge. The heat pump works in reverse so transferring the heat from outside into the building.
There are two types of heat pump:
An air/water heat pump – this unit absorbs the heat from the air, and via the refrigeration system transfers this heat into the water circuit which is then pumped into the building.
A water/water heat pump – this unit absorbs heat from the ground and transfers this heat into a separate water circuit which is then pumped into the building.
The air/water heat pump is located outside and looks like a large air conditioning unit. There is a fan on this unit which transfers the heat from the air into the refrigeration circuit. The heat from the refrigeration circuit is then transferred via a heat exchanger into the water circuit. This hot water is then pumped into the house, and heats the house normally via under floor heating circuits.
The water/water heat pump sometimes known as the Geothermal or Ground Source heat pump can be located inside the building. This has two water circuits: the first water circuit comprises pipes underground outside which absorb the heat from the ground and transfer it into the refrigeration circuit within the heat pump. Via a heat exchanger this heat is then transferred from the refrigeration circuit into the secondary heating circuit which is connected to the under floor heating circuits within the house.
The advantage of the Geothermal heat pump is that the unit is mounted inside, for example, in a basement, and therefore cannot be seen and normally not heard. In some cases it can be more efficient than the air/water heat pump. However Geothermal heat pump systems are more expensive as it is necessary to install additional pipe work outside as well as excavation works outside.
In the Algarve it is questionable how much more efficient the Geothermal heat pump can be. In most cases, even during wintertime the air temperature is relatively high and therefore air/water heat pumps can operate efficiently in the Algarve even during wintertime. However, having said that, with the cold winters now being experienced in the Algarve the Geothermal heat pump is an option that should be seriously considered as the ground temperature is much more stable than the air temperature. The other advantage is that the Geothermal heat pump can run at night time on low cost electricity since the ground will maintain a similar temperature during both the night and the day unlike the air temperature which can drop considerably at nighttime during the winter months.
Both types of heat pump can operate in reverse mode thus providing cooling as well as heating within the building. The Geothermal system will tend to be more efficient during summertime because the ground temperature will remain relatively low in comparison to the higher air temperatures during the summer months.
Both types of heat pump system are extremely efficient in comparison to other types of heating such as gas or electric heating. However it is important always to consider solar heating particularly here in the Algarve. The best solution therefore, for any villa is to have a solar heating system as the primary source of heat backed up by air or Geothermal heat pumps. Solar systems can be used for all types of heating including under floor heating and pool heating as well as heating of sanitary hot water. Heat pumps can be used as back up for these systems with the exception of sanitary hot water where it is best to use gas or electric back up.
Therefore in the Algarve, in many cases it is quite adequate to use air/water heat pumps but on some projects it may be more appropriate to use Geothermal type heat pumps. Every project is different and therefore it is best to seek professional advice on these systems so that the most appropriate type of heat pump can be chosen as well as other energy efficient systems and associated renewable energy systems.
For more information, please call 282 960 969 or email
