Air Source Heat Pump Water Heaters

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In the energy climate of today, energy costs continue to increase. Wasted energy has become economically unfeasible for most companies and the need to save the worlds resources is just another responsible reason coming on the heels of sound financial planning.

Environmentally Engineered Equipment, Inc., has developed a full and comprehensive line of equipment to fit the needs of clients with many and diverse requirements.

Heat Harvester Air Source Heat Pump Water Heater can keep your building warm in the winter and cool in the summer. Our air-source heat pump pulls its heat indoors from the outdoor air in the winter and from the indoor air in the summer. A GHP extracts heat from the indoor air when it's hot outside, but when it's cold outside, it draws heat into a building from the ground, which maintains a nearly constant temperature of 50° to 60°F. This fact sheet focuses on air-source heat pumps, which comprise the majority of all building heat pump applications.

A Heat Harvester Air Source Heat Pump can provide efficient heating and cooling for your building, especially if you live in a warm climate. When properly installed, an air-source heat pump can deliver one-and-a-half to three times more heat energy to a building compared to the electrical energy it consumes. This is possible because a heat pump moves heat rather than converting it from a fuel, like in combustion heating systems.

How it Works
You might be wondering how an air-source heat pump uses the outdoor winter air to heat a building. Believe it or not: heat can be harvested from cold outdoor air down to about 40°F. And this can be accomplished through a process you're probably already familiar with—refrigeration.

Basically, a heat pump's refrigeration system consists of a compressor, and two coils made of copper tubing, which are surrounded by aluminum fins to aid heat transfer. The coils look much like the radiator in your car. Like in a refrigerator or air-conditioner, refrigerant flows continuously through pipes, back and forth from the outdoor coils. In the heating mode, liquid refrigerant extracts heat from the outside coils and air, and moves it inside as it evaporates into a gas. The indoor coils transfer heat from the refrigerant as it condenses back into a liquid. A reversing valve, near the compressor, can change the direction of the refrigerant flow for cooling as well as for defrosting the outdoor coils in winter.

When outdoor temperatures fall below 40°F, a less-efficient panel of electric resistance coils, similar to those in your toaster, kicks in to provide indoor heating. This is why air-source heat pumps aren't always very efficient for heating in areas with cold winters. Fuel-burning furnaces generally can provide a more economical way to heat buildings in cooler climates.

The efficiency and performance of today's air-source heat pumps is one-and-a-half to two times greater than those available 30 years ago. This improvement in efficiency has resulted from technical advances and options such as:

• Thermostatic expansion valves for more precise control of the refrigerant flow to the indoor coil
• Variable speed blowers, which are more efficient and can compensate for some of the adverse effects of restricted ducts, dirty filters, and dirty coils
• Improved coil design
• Improved electric motor and two-speed compressor designs
• Copper tubing, grooved inside to increase surface area.

Types of Air-Source Heat Pumps
You can use a central heat pump to heat and cool a whole house. Most central heat pumps are split-systems—that is, they each have one coil indoors and one outdoors. Supply and return ducts connect to a central fan, which is located indoors. The fan, often called an air handler or blower, circulates air throughout the house. The fan also usually contains electric resistance coils (some units now have a gas-fired furnace option). The heated or cooled air circulates from the fan to the supply ducts, and openings in the building called supply registers. Return registers and ductwork return the air to the fan to be heated.