Heat pumps and energy
FEATURE 27
By
Rory Macnamara – technical input by Derick Gomez of MD Water
The Heat Pump – How does it work ?
Simply put , a heat pump is a device that uses a small amount of energy to move heat from one location to another . Heat pumps are typically used to pull heat out of the air or ground to heat a home or office building , but they can be reversed to cool a building . A heat pump offers one a way to use electricity to heat water efficiently . Where a geyser uses three units of electrical energy to produce three units of heat energy , a heat pump converts just one unit of electrical energy into four units of heat energy .
One of the big advantages over solar is that one does not need sun as these systems run day or night , rain or shine to deliver hot water at a fraction of the cost . Bear in mind that like solar , the investment in a heat pump has a medium-term ROI and it is important to get the installation done by an accredited specialist to ensure that all components of the system are high quality and are properly matched to your client ’ s requirements .
Whether a straightforward installation or part of a rational design , the application is critical and can only be done by a qualified engineer or installer / contractor .
“ The heat pump can contribute to reducing further energy consumption .”
We extracted this intro from www . savingenergy . co . za
Many heat pumps are imported and the plumber or air-conditioning contractor , in promoting the use of heat pumps to a client , needs to consider import versus local . As always , the unit must suit the application and full appreciation of the actual ambient temperature at the site where the unit is to be installed . Failure to do this will result in the heat pump not performing correctly .
Hot water storage heaters , commonly referred to as geysers , can be supported by a heat pump and correctly installed can reduce electricity costs . A South African company has a local patent to retrofit existing geysers with a copper element that retains the heat consistently without heat loss . SANS 151 calls for minimum heat loss as well as geysers achieving a B energy rating , and the heat pump can contribute to reducing further energy consumption .
There are basically four types of hot water heaters :
• Conventional storage water heaters store and heat in a tank , making use of electricity or gas .
• Tankless or demand type water heaters which heat water directly on its way through the pipes to the outlet . Correct pipe sizing is critical .
• Solar Water Heaters use the sun to warm up water and save on energy . Takes longer time to warm the water and runs out quicker on average . This type of heater must be correctly positioned to gain the optimum benefit .
• Heat Pump water heaters work off ambient warmth from the air and compress it to heat up the water i . e ., they convert one kW to four kW , making them highly efficient and cost saving .
Plumblink Durban DC Technical and Demo Centre
Typical installation of heat pump to geyser ( seen in the Plumblink Durban DC Technical and Demo Centre ).
June 2023 Volume 29 I Number 4 www . plumbingafrica . co . za