Unlike air-source heat pumps, ground-source heat pumps require a ground heat exchanger to collect and dissipate heat underground. As with air-source heat pumps, ground-source heat pump systems are available in a range of different efficiencies. The vapour is then compressed, which reduces its volume and causes it to heat up. In Canada, where air temperatures can go below 30C, ground-source systems are able to operate more efficiently because they take advantage of warmer and more stable ground temperatures. The Region 5 HSPF is most reflective of heat pump performance in the Ottawa region. There has been a dramatic improvement in the efficiency of ground-source systems. While many colder Canadian regions are still classified under Region 5, the HSPF value provided may not fully reflect actual system performance. While efficiencies have continually improved, they still remain below 100%, meaning that not all the available energy from combustion is used to heat the air. If you have an extra existing well, your heat pump contractor should have a well driller ensure that it is suitable for use as a rejection well. However, this calculation is typically limited to a single region, and may not fully represent performance across Canada. Since air-source heat pumps have a minimum outdoor operating temperature (between -15C to -25C) and reduced heating capacity at very cold temperatures, it is important to consider a supplemental heating source for air-source heat pump operations. Ductless residential air-source heat pumps are typically installed with a single stage heating/cooling thermostat or in many instances a built in thermostat set by a remote that comes with the unit. Most ground-source heat pump units are covered by a one-year warranty on parts and labour, and some manufacturers offer extended warranty programs. Payback period is dependent on a variety of factors such as soil conditions, heating and cooling loads, the complexity of HVAC retrofits, local utility rates, and the heating fuel source being replaced. Achieving a reduction in your energy bills greatly depends on the price of electricity in relation to other fuels such as natural gas or heating oil, and, in retrofit applications, what type of system is being replaced. A performance standard specifies tests and test conditions at which heat pump heating and cooling capacities and efficiency are determined. Properly installed, these pipes will last anywhere from 25 to 75 years. Care should be taken if considering their use with high temperature radiators that require water temperatures above 60C, as these temperatures generally exceed the limits of most residential heat pumps. Note: HSPF factors are provided for AHRI Climate Zone V, which has a similar climate to Ottawa. To support understanding of this section, refer to the earlier section called An introduction to Heat Pump Efficiency for an explanation of what HSPFs and SEERs represent. For enquiries,contact us. The plenum is an air compartment that forms part of the system for distributing heated or cooled air through the house. This allows the heat pump to operate more efficiently, with typical efficiencies well over 100%, i.e. Air-Water Heat Pumps: Less common in Canada, air-water heat pumps heat or cool water, and are used in homes with hydronic (water-based) distribution systems such as low temperature radiators, radiant floors, or fan coil units. Unlike air-source heat pumps, ground-source systems do not require a defrost cycle. In a closed-loop system, the antifreeze mixture or refrigerant is pumped back out to the underground piping system to be heated again. Your well and pump combination should be large enough to supply the water needed by the heat pump in addition to your domestic water requirements. Sometimes a low-cost financing plan or incentive is offered for approved installations. Units in the high efficiency range tend to use multi-or variable speed compressors, variable speed indoor fans, or both. This vapour passes through the reversing valve to the accumulator, which collects any remaining liquid before the vapour enters the compressor. If you are exploring options to heat and cool your home or reduce your energy bills, you might want to consider a heat pump system. This is due to the fact that underground temperatures are higher in winter than air temperatures. This device helps to transfer thermal energy between the source and sink. Heat pumps are a proven and reliable technology in Canada, capable of providing year-round comfort control for your home by supplying heat in the winter, cooling in the summer, and in some cases, heating hot water for your home. If the heat pump airflow exceeds the capacity of your existing ducting, you may have noise issues or increased fan energy use. However, going up the hill requires a lot more work, as the bike is moving against the natural direction of motion. While an undersized system will still operate efficiently, you may not get the anticipated energy savings due to a high use of a supplemental heating system. The first type controls the operation of the electric resistance supplementary heating system. Heating energy cost savings compared with electric furnaces are around 65%. Demand-frost controls monitor airflow, refrigerant pressure, air or coil temperature and pressure differential across the outdoor coil to detect frost accumulation. Likewise, if a heat pump is oversized, the desired energy savings may not be realized due to inefficient operation during milder conditions. Programmable heat pump thermostats are available today from most heat pump manufacturers and their representatives. Ground-source systems continue to operate regardless of the outdoor temperature, and as such are not subject to the same sort of operating restrictions. If you live in an area where electricity is expensive, your operating costs may be higher. Apart from sizing, several additional performance factors should be considered: Air-source heat pumps should be installed by a qualified contractor. Stage one calls for heat from the heat pump if the temperature falls below the pre-set level. CanmetENERGY: science at the service of all Canadians. The expansion device lowers the pressure created by the compressor. Heat pump systems generally supply a greater volume of airflow at lower temperature compared to furnace systems. The operating costs of a ground-source system are usually considerably lower than those of other heating systems, because of the savings in fuel. As a result, the demand-frost method is generally more efficient since it starts the defrost cycle only when it is required. Regardless of the approach used, the system should be designed to prevent any environmental damage. Split systems allow the coil to be added to a forced-air furnace, and use the existing blower and furnace. Lower-end systems typically employ two stage compressors, relatively standard size refrigerant-to-air heat exchangers, and oversized enhanced-surface refrigerant-to-water heat exchangers. DX systems use refrigeration-grade copper tubing. Poor water quality can cause serious problems in open systems. Ground-source heat pump systems have three main components: the heat pump unit itself, the liquid heat exchange medium (open system or closed loop), and a distribution system (either air-based or hydronic) that distributes the thermal energy from the heat pump to the building. You will not receive a reply. Air-source heat pumps have a service life of between 15 and 20 years. Similarly, as energy is added to a sink, its temperature increases. The higher efficiency of the heat pump can translate into significant energy use reductions. The vapour is then compressed, reducing its volume and causing it to heat up. Plastic piping must be thermally fused, and there must be good earth-to-pipe contact to ensure good heat transfer, such as that achieved by Tremie-grouting of boreholes. Because of this, most air-source installations require a supplementary heating source to maintain indoor temperatures during the coldest days. For hydronic systems, both the source and sink heat exchangers and compressor are in a single cabinet. Below this outdoor ambient temperature, the heat pump can supply only part of the heat required to keep the living space comfortable, and supplementary heat is required. To do this, the heat pump switches into defrost mode. In a similar manner, heat naturally flows from places with higher temperature to locations with lower temperatures (e.g., in the winter, heat from inside the building is lost to the outside). Residential units range in rated size (closed loop cooling) of 1.8 kW to 21.1 kW (6 000 to 72 000 Btu/h), and include domestic hot water (DHW) options. Stage two calls for heat from the supplementary heating system if the indoor temperature continues to fall below the desired temperature. Relative savings will depend on whether you are currently using electricity, oil or natural gas, and on the relative costs of different energy sources in your area. Ground-source heat pumps consist of two main parts: A ground heat exchanger, and a heat pump. It is recommended that a heating and cooling professional be retained to undertake the required calculations. There are two types of outdoor thermostats used with these systems. Also, be sure that vents and air registers in your home are not blocked by furniture or carpeting, as inadequate airflow to or from your unit can shorten equipment lifespans and reduce efficiency of the system. The antifreeze solution must be acceptable to local environmental officials. So how does a heat pump heat or cool your home? Neither vertical nor horizontal loops have an adverse impact on the landscape as long as the vertical boreholes and trenches are properly backfilled and tamped (packed down firmly). As a result, a ground-source heat pump can provide more heat over the course of the winter than an air-source heat pump. The performance testing standards for air-source heat pumps are CSA C656, which (as of 2014) has been harmonised with ANSI/AHRI 210/240-2008, Performance Rating of Unitary Air-Conditioning & Air-Source Heat Pump Equipment. A closed-loop system draws heat from the ground itself, using a continuous loop of buried plastic pipe. Indoor air is heated by the heat pump. Consult a local heating and cooling professional to size, install, and maintain your equipment to ensure efficient and reliable operations. This process is reversed in cooling mode, and thermal energy is extracted from the hydronic system and rejected to the outdoor air. Actual HSPFs may be lower in regions with increased heating degree days. For cost-effectiveness, the system should generally be sized to cover the majority of the households annual heating energy requirement. Minimum performance for Canada as a whole, and typical ranges for market-available products, are summarized below for heating and cooling. It is important that horizontal and vertical loops be installed by a qualified contractor. They allow for a significant reduction in our energy consumption. Will I need to make additional modifications to my home? Also, be sure that all manufacturers' instructions are followed carefully. The plenum , only seen in ducted installations, is part of the air distribution network. Programmable control to allow for user selection of automatic heat pump or fan-only operation, by time of day and day of the week. If the installation is a retrofit, the existing duct system should be carefully examined to ensure that it is adequate. They can be further classified according to the type of installation: Air-air systems are more efficient when the temperature difference between inside and outside is smaller. During the cooling cycle, the heat pump also dehumidifies the indoor air. Some of this excess heat can be used to preheat domestic hot water. You may need to enlarge your pressure tank or modify your plumbing to supply adequate water to the heat pump. The incremental cost of such a system can be recovered through energy cost savings over a period as low as 5 years. Improper installation may result in poorer heat pump performance. No need for an outdoor thermostat control on add-on heat pumps. Of particular importance when considering efficiency is the role of new compressor designs in improving seasonal performance. These aspects are discussed in more detail in the Air-Source Heat Pumps and Ground-Source Heat Pumps sections. The active cooling cycle is basically the reverse of the heating cycle. That is why our researchers are hard at work trying to adapt air-source heat pumps to our Canadian climate. The heat pump simply removes or adds heat to the water; no pollutants are added. They are also an option when replacing existing air conditioning systems, as the incremental cost to move from a cooling-only system to a heat pump is often quite low. The only change in the water returned to the environment is a slight increase or decrease in temperature. Ground-source heat pumps generally have a life expectancy of about 20 to 25 years. It is determined by dividing the cooling capacity of the heat pump in Btu/h by the electrical energy input in Watts (W) at a specific temperature. What Is a Heat Pump, and How Does It Work? This means that, for units with a COP of 5, 5 kilowatt hours (kWh) of heat are transferred for every kWh of electricity supplied to the heat pump. A heat pump is an electrically driven device that extracts heat from a low temperature place (a source), and delivers it to a higher temperature place (a sink). Water inside the building is heated. The pipe is connected to the indoor heat pump to form a sealed underground loop through which an antifreeze solution or refrigerant is circulated. As the outdoor air temperature drops, COPs are lower, as the heat pump must work across a greater temperature difference between the indoor and outdoor space. The cycle described above is reversed to cool the house during the summer. Using these questions as a guide, this booklet describes the most common types of heat pumps, and discusses the factors involved in choosing, installing, operating, and maintaining a heat pump. Moisture in the air passing over the indoor coil condenses on the coil's surface and is collected in a pan at the bottom of the coil. To help with this process, NRCan has developed an Air-Source Heat Pump Sizing and Selection Guide. Actual seasonal efficiencies may vary depending on your region. Particles and other matter can clog a heat pump system and make it inoperable in a short period of time. The vapour is then compressed, reducing its volume and causing it to heat up. To this end, a compressor inside the device uses electricity to increase the temperature of the heat extracted from the outside air. Finally, the reversing valve directs the now-hot gas to the condenser coil, where it gives up its heat to the air or hydronic system to heat the home. The outdoor unit is where heat is transferred to/from the outdoor air in an air-source heat pump. Below this temperature, only the supplementary heating system operates. But the road to a low-carbon future has its challenges. In ground water or antifreeze mixture systems, it then passes through the refrigerant-filled primary heat exchanger. Unlike air-source heat pumps, where one heat exchanger is located outside, in ground-source systems, the heat pump unit is located inside the home. Typical water temperatures entering the ground-source heat pump are generally above 0C, yielding a COP of around 3 for most systems during the coldest winter months. You should also have your water tested for acidity, hardness and iron content before installing a heat pump. In some cases, additional modifications to the ductwork or electrical services may be required to support your new heat pump installation. This leaves bare areas that can be restored with grass seed or sod. Most air-source systems shut off at one of three temperatures, which can be set by your installation contractor: Most supplementary systems can be classed into two categories: An outdoor temperature sensor shuts the heat pump off when the temperature falls below the pre-set limit. Installation costs vary depending on the type of ground collector and the equipment specifications. For newer models, this can range from between -15C to -25C. As in the heating cycle, the liquid refrigerant passes through the expansion device, changing to a low-pressure liquid/vapour mixture. Installation of an open system is often subject to local zoning laws or licensing requirements. It is important that the ground heat exchanger be well matched to the heat pump capacity. Your contractor will be able to give you guidance on your specific case. Steady state metrics include: Coefficient of Performance (COP): The COP is a ratio between the rate at which the heat pump transfers thermal energy (in kW), and the amount of electrical power required to do the pumping (in kW). At 8C, COPs can range from 1.1 to 3.7. While an open system drains water from a well, a closed-loop system recirculates the antifreeze solution in the pressurized pipe. While the supplemental heating system operates less frequently, under warmer ambient conditions, the heat pump produces too much heat and the unit cycles on and off leading to discomfort, wear on the heat pump, and stand-by electric power draw. Horizontal loop installations use trenches anywhere from 150 to 600 mm (6 to 24 in.) The amount of frost buildup depends on the outdoor temperature and the amount of moisture in the air. The indoor coil is located in the ductwork, close to the furnace. The most common type of thermostat used is the "set and forget" type. It also replaces CAN/CSA-C273.3-M91, Performance Standard for Split-System Central Air-Conditioners and Heat Pumps. A number of publications explaining how to do this are available from Natural Resources Canada. This booklet should not replace working with a contractor or energy advisor, who will ensure that your installation meets your needs and desired objectives. The ground water is pumped to a heat exchanger, where thermal energy is extracted and used as a source for the heat pump. A variety of efficiency metrics are used in manufacturer catalogues, which can make understanding system performance somewhat confusing for a first time buyer. The liquid refrigerant absorbs heat from the indoor air and boils, becoming a low-temperature vapour. These units heat or cool the air inside your home, and represent the vast majority of air-source heat pump integrations in Canada. The unit takes heat out of the indoor air and rejects it outside. This is how a heat pump operates in cooling mode, and is the same principle used by air conditioners and refrigerators. The ground water exiting the heat exchanger is then reinjected into the aquifer. This will reduce the savings that you might have expected to achieve by installing the heat pump. A new performance standard that aims to better represent performance of these systems in Canadian regions is currently under development. The major benefit of using an air-source heat pump is the high efficiency it can provide in heating compared to typical systems like furnaces, boilers and electric baseboards. It then goes to the indoor coil, which acts as the evaporator. On average, a well designed ground-source system will yield savings that are about 10-20% more than would be provided by a best in class, cold climate air-source heat pump sized to cover most of the building heating load. Copper tubing is used in the case of DX systems. These types of systems contain two key components: Depending on how the heat pump and ground heat exchanger interact, two different system classifications are possible: Ground-source heat pumps can serve a suite of comfort needs in your home, including: Heating and active cooling operations are described in the following section. This vapour passes through the reversing valve to the accumulator, which collects any remaining liquid, and then to the compressor. Actual energy savings will vary depending on the local climate, the efficiency of the existing heating system, the costs of fuel and electricity, the size of the heat pump installed, borefield configuration and the seasonal energy balance, and the heat pump efficiency performance at CSA rating conditions. It is important to note that the efficiency of the heat pump depends greatly on the temperatures of the source and sink. This liquid returns to the expansion device, and the cycle is repeated. Find an explanation of single speed and variable speed heat pumps in the Air-Source Heat Pump section. New heat pump systems should be designed according to established practice. In some regions and cases, this added cost can be recouped in a relatively short time period through the utility cost savings. Region 5 would cover most of the southern half of the provinces in Canada, from the B.C interior through New BrunswickFootnote 1. Today, air-source heat pumps represent one of the most promising technologies for heating and cooling our homes. At the same time the outdoor fan, which normally blows cold air over the coil, is shut off in order to reduce the amount of heat needed to melt the frost. Energy Efficiency Ratio (EER): The EER is similar to the COP, and describes the steady-state cooling efficiency of a heat pump. This sends hot gas to the outdoor coil to melt the frost. This section presents the basics of how a heat pump works, and introduces different system types. EER is strictly associated with describing the steady-state cooling efficiency, unlike COP which can be used to express the efficiency of a heat pump in heating as well as cooling. The performance testing standards for ground-source systems are CSA C13256 (for secondary loop systems) and CSA C748 (for DX systems). Selecting the source and sink for your heat pump system goes a long way in determining the performance, capital costs and operating costs of your system. The second type simply shuts off the air-source heat pump when the outdoor temperature falls below a specified level. The cycle can be initiated every 30, 60 or 90 minutes, depending on the climate and the design of the system. To appropriately size your heat pump system, it is important to understand the heating and cooling needs for your home. Heat pumps are very efficient heating and cooling systems and can significantly reduce your energy costs. This helps to maintain peak efficiency at all times, including during milder conditions when there is lower-demand on the system. This contrasts with furnace systems, which deliver a smaller volume of air, but heat that air to higher temperatures (between 55C and 60C). If a heat pump is undersized, you will notice that the supplemental heating system will be used more frequently. The installer consults with you prior to setting the desired temperature. Ground-source heat pumps use the earth or ground water as a source of thermal energy in heating mode, and as a sink to reject energy when in cooling mode. It is important to work with your contractor or energy advisor to get an estimate of the economics of heat pumps in your area, and the potential savings you can achieve. Sources: Two sources of thermal energy are most commonly used for heating homes with heat pumps in Canada: Sinks: Two sinks for thermal energy are most commonly used for heating homes with heat pumps in Canada: Furnaces and boilers provide space heating by adding heat to the air through the combustion of a fuel such as natural gas or heating oil. Unlike conventional thermostats, these thermostats achieve savings from temperature setback during unoccupied periods, or overnight. Actual savings in your house will depend on a number of factors, including your local climate, efficiency of your current system, size and type of heat pump, and the control strategy. Be sure to change or clean your air filter every 3 months, as clogged filters will decrease airflow and reduce the efficiency of your system. Time-temperature defrost is started and ended by a pre-set interval timer or a temperature sensor located on the outside coil. The electricity input into the heat pump is used to transfer thermal energy between two locations. If you have an air-based distribution system, you can also support more efficient operations by replacing or cleaning your filter every 3 months. Here are some common terms you may come across while investigating heat pumps. Variable speed air-source heat pumps are now available that are designed to vary the capacity of the system to more closely match the heating/cooling demand of the house at a given moment. In thinking of the home as a system, it is recommended that heat losses from your home be minimized from areas such as air leakage (through cracks, holes), poorly insulated walls, ceilings, windows and doors. The reversing valve controls the direction of flow of the refrigerant in the heat pump and changes the heat pump from heating to cooling mode or vice versa. You should also ensure that your air vents and registers are not blocked by any furniture, carpeting or other items that would impede airflow. Operating temperatures in the hydronic system are critical when evaluating air-water heat pumps. The heat from the hot gas is transferred to the indoor air, causing the refrigerant to condense into a liquid. Units of measurement for capacity, or power use: Air-source heat pumps use the outdoor air as a source of thermal energy in heating mode, and as a sink to reject energy when in cooling mode. A condensate drain connects this pan to the house drain. The supplementary heating system only provides heat that is beyond the rated capacity of the ground-source unit. Every day, scientists and engineers at Natural Resources Canadas CanmetENERGY research centres are working to find low-cost, clean-energy solutions to this issue. Depending on the size of your new heat pump, some modifications may be needed to your ductwork to avoid added noise and fan energy use. A heat pump uses additional electrical energy to counter the natural flow of heat, and pump the energy available in a colder place to a warmer one.