Heat Pumps and Energy Saving
Most heat pumps are designed for cooling as well as heating and it is in this way that the heat pump is the most effective. Because of its energy-saving features and a renewed interest in the heat pump.
It is clear that heat pumps are very energy intensive, and therefore is ecologically clean. Heat pumps offer the most efficient way of heating and cooling in many applications, as they can use renewable heat in our surroundings. Even at temperatures, which we believe to cold air, land and water contain useful thermal energy, which is constantly updated by the sun. With a little more power, a heat pump can raise the temperature of the heat energy to the level required. Similarly, heat pumps can also use waste heat sources, such as industrial processes, equipment for cooling or ventilation, extracted from the buildings. Typical electricity, heat pump will need to be 100 kW-h of electric power to turn 200 kWh freely available for environmental or waste heat from 300 kW useful heat.
Thanks to this unique ability, heat pumps can radically improve the energy efficiency and environmental value of any heating system, which is managed by primary energy resources, such as fuel or electricity.
The following six facts should be considered when any heat supply system is intended for (IEA-HPC, 2001):
- Direct combustion for heat production is not the most efficient use of fuel.
- Heat pumps are more efficient because they use renewable energy as a low-temperature heat.
- If the fuel for conventional boilers is redirected to power electric heat pumps, about 35-50% less fuel is required, resulting in 35-50% less emissions.
- About 50% savings in electric heat pumps are driven CHP, or cogeneration systems.
- Whether fossil fuels, nuclear energy or renewable energy sources used to generate electricity, electric heat pumps make much better use of these resources, than resistance heaters.
- Fuel consumption, and hence the intensity of the emission, absorption, or gas engine heat pump is around 35-50% less than a conventional boiler.
In the past, most heat pumps were in the air-to-air and air-source type. Air source heat pumps rely on open air for their heat source. Although the cold outside air contains a certain amount of heat, and the temperature falls, the heat pump has to work harder and reduces efficiency. In very cold weather, air source heat pump alone cannot provide enough heat, and as additional or redundant heat should be provided. This can significantly increase spending on heating. GSHPs extract heat from the ground or water below the surface. Because groundwater and underground water temperature constant 10 - 13 C all year round, such a system is much more efficient.
It depends on the cost of electricity, oil and propane in your area. As a rule, GSHP can produce heat, average savings of 10-15% in comparison natural gas, 40% cost savings compared with fuel oil and 50% cost savings compared with propane; air conditioning savings average of 40-60% compared to conventional systems (EESC, 2001).
Heat pump water heaters extract heat from the ambient air for heating water in a storage tank and can be fueled by electricity or gas. These furnaces are essentially the same performance as electrical resistance, water heaters, except that efficiency is usually in 2-2, 5 times higher. The energy factor in the heaters of water varies from 1.8 to 2.5, compared with 0.88-0.96 for electric resistance system. Heat pump water heaters cool and dehumidify the air around the evaporator coil. This may be an advantage where cooling is desirable, and a disadvantage when cooling is undesirable. Some heat pump water heaters are designed to recover waste heat from the whole house ventilation systems.
Heat pump water heaters available on sale, with the payback period is usually from 2 to 6 years, depending on the hot water and efficiency water heater system will be replaced. When buying a new heat pump, the buyer shall check the assessment of the effectiveness of the proposed device. High efficiency rating will result in lower operating costs. The efficiency of the heat pump to the SEER, in particular, from 10.0 to more 15.0. To split systems with an outdoor unit and an indoor coil, effectiveness varies depending on the result of the match between the internal cooling coil and the external condensing unit. The manufacturer should be consulted to determine the overall effectiveness. American refrigeration Institute publishes an annual list of directories various combinations of outdoor unit and indoor coil with their SEER rating. Most major manufacturers product lines are included in this directory...