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HEAT PUMPS continued..
Air source heat pumps rely on outdoor air for their heat. Now there are also ground source (also called geothermal, geoexchange, or earth source) heat pumps that extract heat from the ground or from water, below or on the surface. Because ground and ground water temperatures are a constant 7°-13°C (45°-55°F) year-round, this type of system is much more efficient. However, for ground source heat pumps it is important to replace the heat used from the ground in the winter with a sizeable cooling load in the summer. An unbalanced system that requires much more winter heating than summer cooling can lead to inefficiencies if the ground temperature cools and can no longer provide adequate heat in the winter. Air source heat pumps increase energy efficiency in areas where the winter low temperatures rarely drop below -18C. In regions with colder winters, it will be necessary to use a ground source heat pump. Under optimal conditions a heat pump can provide three times the amount of heat energy than the electrical energy it consumes. A heat pump is designed to move heat from one place to another. The outdoor coil of the heat pump absorbs heat from the outside air and transfers it to your home. In hot weather, the heat pump operates in reverse to provide cooling. It transfers heat from within your home to the outdoors. In recent years, heat pump efficiency has increased due to the incorporation of the following improvements: * Variable speed blowers, compressors and motors – This equipment provides variable speeds of operation to optimize performance and efficiency. Heat pumps utilizing multi-speed components will typically start in the first stage or low speed. If comfort levels or control settings cannot be satisfied with the first stage, the second stage or high speed will activate. Some heat pump systems have more than two stages or speeds of operation. Larger coil surface areas – Large surface coils provide maximum heat transfer efficiency. Time delays - Time delays vary the on and off cycles of compressors, motors and supplemental heat packages. * Expansion valves – Expansion valves control the flow of refrigerant in proportion to the load on the evaporator. Compared with other types of fixed metering devices, expansion valves are able to exercise control over a much wider range of operating conditions. HEAT PUMP OPERATION Follow these guidelines to ensure efficient, comfortable operation of heat pumps: * In the heating mode, do not set the temperature back at night or when you are out, unless you are using a "smart" programmable heat pump thermostat. Setting back a standard heat pump thermostat can increase energy consumption because it engages the supplemental heaters to bring the temperature back to the desired setpoint. * Replace filters regularly. Vacuum dirt and dust from the indoor coil once a year to prevent restricted airflow. Adequate airflow through a heat pump system is critical to ensure efficient and comfortable operation. * Keep supply vents open and free from obstruction. Closing off supply vents will restrict airflow and reduce system efficiency as well as reduce the life of the compressor. * Keep the coil in the outdoor unit clear of snow, leaves and other debris so that airflow is not restricted. * In belt-driven indoor units, check belt tension once a year and adjust if loose. The system should be adjusted annually by a trained professional. HOUSE SMART HOME IMPROVEMENTS SPECIALIZES IN:
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