If you are exploring the heating and cooling options for a new house or looking for ways to reduce your energy bills, you may be considering a heat pump.
A heat pump can provide year-round climate control for your home by supplying heat to it in the winter and cooling it in the summer. Some types can also heat water. In general, using a heat pump alone to meet all your heating needs may not be economical. However, used in conjunction with a supplementary form of heating, such as an oil, gas or electric furnace, a heat pump can provide reliable and economic heating in winter and cooling in summer. If you already have an oil or electric heating system, installing a heat pump may be an effective way to reduce your energy costs. Nevertheless, it is important to consider all the benefits and costs before purchasing a heat pump. While heat pumps may have lower fuel costs than conventional heating and cooling systems, they are more expensive to buy. It is important to carefully weigh your anticipated fuel savings against the initial cost. It is also important to realize that heat pumps will be most economical when used year round.
Investing in a heat pump will make more sense if you are interested in both summer cooling and winter Heating. In addition to looking at cost, you should consider other factors. How much space will the equipment require? Will your supply of energy be interrupted on occasion? If so, how often? Will you need changes or improvements to your ducting system? How much servicing will the system need, and what will it cost? Becoming fully informed about all aspects of home heating and cooling before making your final decision is the key to making the right choice. This booklet describes the most common types of heat pumps, and discusses the factors involved in choosing, installing, operating, and maintaining a heat pump. A brief section on the cost of operating different types of heat pumps and conventional electric heating system is also included.
A heat pump is an electrical device that extracts heat from one place and transfers it to another. The heat pump is not a new technology; it has been used in Canada and around the world for decades. Refrigerators and air conditioners are both common examples of this technology.
Heat pumps transfer heat by circulating a substance called a refrigerant through a cycle of evaporation and condensation (see Figure 1). A compressor pumps the refrigerant between two heat exchanger coils. In one coil, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings.
The refrigerant is then compressed en route to the other coil, where it condenses at high pressure. At this point, it releases the heat it absorbed earlier in the cycle. Refrigerators and air conditioners are both examples of heat pumps operating only in the cooling mode. A refrigerator is essentially an insulated box with a heat pump system connected to it. The evaporator coil is located inside the box, usually in the freezer compartment. Heat is absorbed from this location and transferred outside, usually behind or underneath the unit where the condenser coil is located. Similarly, an air conditioner transfers heat from inside a house to the outdoors. The heat pump cycle is fully reversible, and heat pumps can provide year-round climate control for your home –heating in winter and cooling and dehumidifying in summer. Since the ground and air outside always contain some heat, a heat pump can supply heat to a house even on cold winter days. In fact, air at –18°C contains about 85 percent of the heat it contained at 21°C.
An air-source heat pump absorbs heat from the outdoor air in winter and rejects heat into outdoor air in summer. It is the most common type of heat pump However, ground-source (also called earth-energy, geothermal, geo exchange) heat pumps, which draw heat from the ground or ground water, are becoming more widely used,
An air/water heat pump makes it much cheaper to heat your home and hot water. You can reduce your heating costs by up to 65%, although the exact figure depends on several factors such as where you live, the size of your house and whether or not you use the system for cooling too. The initial investment is relatively low since an air/water heat pump, unlike a ground source heat pump, does not require any ground drilling. The efficiency of heat pumps positively impacts the speed with which you recover your investment. With energy prices continually rising, you’re unlikely to regret your decision. In fact, you’ll start enjoying savings from the first month.
Another very good reason for choosing a NIBE air/water heat pump is that it has a very low environmental impact. In fact, installing a air/water heat pump can cut your home’s CO2 emissions in half. This is mainly because there is no combustion process involved. The heat pump merely upgrades naturally occurring energy from the air outside to heat your home and hot water. This leads to much lower CO2 emissions than any traditional fossil fuel-based heating system and explains why air/water heat pumps are classified as a renewable energy source.
In the context of ever rising energy costs and climate change, every household is in need Of a heating technology that is future-proof, cost-effective and independent of fossil fuels.
Heat pumps make a significant contribution towards solving the problems associated with increasingly scarce and evermore expensive energy resources – supplying more energy than they consume by tapping into the freely available, inexhaustible solar energy stored in the earth, the ambient air or water and converting this for use in a heating system. In fact, up to 75% of the energy needed by the heating system is extracted from the environment, so the only energy required is electricity needed to drive the heat pump compressor. Put another way, for every 1kWh of electricity used to run the heat pump, up to 4kW of useful heat is provided, giving the heat pump an efficiency of up to 400%.
Whenever fossil fuels such as gas or oil are burnt, carbon dioxide is released. CO2 is the principle contributor to the greenhouse effect which is leading to long term climate change. However as heat pumps extract as Much as 75% of their heating energy from the environment, building carbon emissions for heating can be reduced by as much as 50% compared with gas fuelled heating systems. This is an obvious benefit when considering building regulations Part L compliance, planning obligations requiring minimum contributions from renewable energy and Eco-Home/Code for Sustainable Homes ratings.
The considerable contribution from renewable energy sources also helps to provide running cost savings over fossil fuelled heating systems and arguably more importantly, future proofs the system against future energy price increases. But fuel costs are only part of the story. Unlike gas and oil based systems, heat pumps require no costly regular maintenance or annual safety inspections. And because a heat pump has a reasonable life expectancy of 20 – 25 years, typically twice that of a boiler, the investment costs can be recovered over a longer period meaning the ownership costs over the working life of the system are demonstrably lower.
To put it simply, they’re three times more efficient! With conventional oil and gas boilers, 1 kWh of input energy provides less than 1 kWh of output energy. Using a NIBE air/water heat pump every 1 kWh of input electrical energy is converted into an average of 3 kWh of heating energy. There is no escaping the obvious conclusion – a heat pump is the absolute best way to get low cost heating and hot water.
At 10°C, the coefficient of performance (COP) of air-source heat pumps is typically about 3.3. This means that 3.3 kilowatt hours (kWh) of heat are transferred for every kWh of electricity supplied to the heat pump. At –8.3°C, the COP is typically 2.3. The COP decreases with temperature because it is more difficult to extract heat from cooler air. Figure 6 shows how the COP is affected by cooler air temperature. Note: however, that the heat pump compares favorably with electric resistance heating (COP of 1.0) even when the temperature falls to –15°C.
|Heater Type||Wood Boiler||Diesel Boiler||Gas Water Heater||Electric Geyser||*Electric boosted Solar||HPWH||HPWH|
|Energy Source||Wood||Diesel||Gas||Electricity||Solar and Electricity||Electricity and Air||Solar, Electricity and Air|
|Unit Energy cost||Rs.5/kg||Rs.50/ltrs||Rs.57/kg||Rs.6/unit||Rs.6/unit||Rs.6/unit||Rs.6/unit|
|Energy Consumption||28 kgs||4.1 ltrs||3.3 kgs||43 units||13.6 units||11.6 units||11.6 units|
|Energy Cost/ton||Rs 140/-||Rs.156/-||Rs.188/-||Rs.258/-||Rs.82/-||Rs.70/-||Rs.70/-|
|Annual Energy Cost||Rs.51,100/-||Rs.56,940/-||Rs.68,620/-||Rs.94,170/-||Rs.29,930/-||Rs.25,550/-||Rs.8,400/-|
|* Annual energy cost has been arrived by considering 120 days of usage (cloudy days)|
If heat pumps were installed in the one million or so new houses built annually in India, we would cut CO2 emissions by over 3,600,000 tons per year. That’s the equivalent of taking about a million cars off the road!
Heat pumps are very efficient heating and cooling systems and can significantly reduce your energy costs. However, there is little point in investing in an efficient heating system if your home is losing heat through poorly insulated walls, ceilings, windows and doors, and by air leakage through cracks and holes.
In many cases, it makes good sense to reduce air leakage and upgrade thermal insulation levels before buying or upgrading your heating system. A number of publications explaining how to do this are available from Natural.
Air Source Heat Pump Water Heating System works with a proven high performance & power saving technology and regarded as 4th generation water heater. It is unique because, approximately 75% of total heat energy generated is absorbed from surrounding air & 25% from electricity.