What are the advantages of heat pump water heaters?

Heat pumps have several benefits and disadvantages:

• Heat pumps can save up to 67% of the energy required to heat water. With water heating by conventional geysers contributing 30-50% of a typical household electricity cost, it means that a heat pump can save 20-33% of the cost. This is more than what would be required from the power ration scheme for the residential sector (10%) or the hospitality industry (20%).
  
  
• Heat pumps are relatively easy to install. All that a heat pump requires is a free air arrangement resulting in it usually being an outside installation. Heat pumps are built to be weather proof and comply with the SANS IP ratings for outdoor electrical installations.
  
• At large centralized water heating installations typically found at commercial buildings such as hotels and hospitals, heat pumps are relatively easy to install. For example, to provide 25000 litres of sanitary hot water at 60ºC per day a heating capacity of typically 100kW would be required. This can be achieved by installing 2 x 50kWthermal heat pumps. These heat pumps can be installed on a hotel premises near the current water heating plant, taking up a space of approximately 10m2.
  
  
• Heat pump installations are more expensive than a conventional electrical resistance heater installation, but a good economic return is possible from the significant savings that can be achieved by it (Please refer the case studies provided. In addition, ESKOM has launched a subsidy program for heat pumps, with this subsidy typically representing a 40-50% reduction in project cost. The economic returns on a large centralized heat pump installation, aided by the ESKOM subsidy, result in competitive payback periods of between 2 and 3.5 years. Payback periods in the residential sector vary between 2 and 4 years. The variance in payback periods is a function of several factors including levels of usage and the ease of installation.
  
• Heat pumps are still dependant on an electricity supply. However, while South Africa is from time to time experiencing rolling blackouts, the electrical supply is sufficient for most of the day. The availability of electricity should at least stay this way, or even improve once energy efficiency programs start to show results. It will therefore not be an issue to have an energy efficient device that is still dependant on an electrical supply. This can be compared to the case of energy efficient lighting; it is still dependant on electricity supply.

Enerflow Heat Pumps

Dr. Martin van Eldik
+27 (0)18 297 0326
mve@mtechindustrial.com