Heat Pumps could play key energy efficiency role as electricity prices rise
Friday, 14 January 2011 |   |  0 comment

Carrier Heat pumps

While solar water heaters have captured the attention of South Africans, heat pumps for  water heating are also emerging as a cost-effective way to deliver large volumes of hot water, particularly where the use of solar collector panels is impractical.

Emergent Energy CEO Frank Spencer says that the prospects for heat pumps for water heating in South Africa are good.

“As the price of electricity increases, the use of heat pumps is also likely to increase,” he adds.
Put simply, a heat pump moves heat from one location that is at a lower temperature, to another location at a higher temperature, through the refrigeration cycle, which 
requires a little mechanical work from a small compressor.

Similar to an air conditioner, a heat pump can be used to provide heating or cooling. A common example is a refrigerator and, more recently, heat pumps have been used for heating water in geysers.
Emergent Energy, part of the Sekunjalo group, supplies a product called the Energie Thermodynamic solar water heater, which combines the benefits of heat pumps with solar collector panels. 
It uses the laws of thermodynamics to produce hot water from the sun, rain and wind.

Using this combined solution, it is said that the net energy consumption, year-on-year, will generally outperform traditional 
large thermal solar water heating (SWH) systems, and air-based heat pumps.
“A regular heat pump sources its heat from the ambient air. It uses a fan-coil heat 
exchanger to do this. So you have ambient air sucked in, and cold air blown out. But the efficiency of a heat pump is a function of your source temperature – so if you can extract heat from a hotter source, your efficiencies will be higher,” explains Spencer.

“This is exactly what our solar heat pump does by sourcing the heat from a solar collector panel. The panel temperature will be, at worst, the same temperature as the air flowing over it, but, at best, it will be very hot in the sun. So it will be a lot more efficient than normal heat pumps,” Spencer adds.
Emergent Energy notes that a reduction of up to 80% in energy consumption for electricity can be achieved using this system.

Financing Solutions

One of the major challenges for off-grid water heating solutions, particularly in the bulk residential sector, is the tendency by developers to optimise their initial building costs instead of focusing on the long-term running cost of the building. Thus, it is quite common for individual electrical geysers to be used in flats, or even to use electric heating where there may be a centralised hot water system in a building.

“This is one of the reasons we have developed a finance model for our solutions, so the developer does not have to bear the cost. In the case of commercial or industrial applications, or retrofits, there is a much stronger case to buy, with paybacks often being below three years,” states Spencer.
Alternatives to buying equipment are offered by Emergent Energy, and include full maintenance leasing, a shared savings model, and a utility model, where Emergent Energy owns and operates the plant and sells the hot water.

Emergent Energy is in discussions with a number of residential apartment blocks, 
hotels and schools to supply the system. 
Spencer notes that the benefits of using the hybrid system are often most notable here, owing to the large volumes of hot water 
required. In addition, the system will still work well where buildings are under trees, have limited roof space, or if aesthetic concerns prevail.

Emergent Energy, which also undertakes large renewable-energy project development, has also just completed the commissioning of two 18-kW solar photovoltaic projects in Botswana.

The company also conducts solar and wind site assessments for large renewable-energy project develops, and undertakes energy audits 
and energy efficiency studies for the agriculture and commercial sectors.
November 20th, 2010