Heat Pumps Systems Basics
Heat pumps use a refrigeration systems to transfer heat from an air or water source to a conditioned space . A reversing valve is used to switch the direction. Heating in winter, cooling in the summer.
In AC mode, Heat is absorbed by the evaporator coil on the inside and released to the outside through the condenser coil. This is a typical of any refrigeration or air conditioning system. Place your hand over the outdoor condenser and you can feel heat being discharged and the inside feels dry and cool.
In heating mode, the heat produced is more energy per kilowatt then is created from resistive heating elements. Typically 2-3 KW of heat for every KW used.
Outdoor air source heat pumps drop the air temperature a few degrees as it passes through the coil. This will cause frost to form when outdoor temperatures are close to freezing. This frost must be thawed and drained often to keep the unit functioning and reduces efficiency of the heat pump.
A ground source systems use an anti-freeze in the transfer fluid and the heat pump can run below -5°C with no need to defrost. No defrost cycle improves the efficiency of the system.
For every kilowatt of power used for a baseboard heater produces 1 kw of heat. If you replace the baseboard heater with a high wall mount fan coil and outdoor heat pump , you can produce ~3kw of heat for every kilowatt of energy used by the compressor. Reducing cost and producing a safe low temperature source of heat.
By 2030 , building codes in BC with require 0 GHG footprint for all new construction. Expect to see photovoltaics on the roofs and wall of buildings and electric heat pumps as the only option heating and cooling home. It will not be long until the gas furnace goes by the way of the 8 track tape.
The electricity produced in BC is mostly Hydroelectric and has a very low greenhouse gas foot print. When compared to natural gas, electric wins. Many renewable sources of energy that are free of fossil fuels are coming on line every day and will be the preferred source of heating.
Standard Heat Pump VS Hyper Heat Pump
Air Source heat pump draw energy from the air. As the air temperature get colder, less heat is absorb by the outdoor coil. Older style heat pump produced very little heat if the temperature outside was below -5̊̊C the output would drop way down and the system would switch to electric. All the older heat pumps always had an electric back up source.
Today's standard air source heat pumps with inverter driven compressors are lot better at producing heat from the air at low temperatures. When is falls to -5̊C, the heat pump will still produce 75% of its maximum output.
Hyper Heat Pump systems use bigger big coils combined with compressor over drive and liquid injection to ramp up the out put as the temperature outside drops. It cost more than a standard heat pump but way cheaper than ground source. These heat pumps have almost the same output at -5̊C as it does a 10̊C which is very important if the heat pump will be your only source of heat.
Ground Source VS Air Source
There are many areas around the Sea to Sky corridor that do not have access to natural gas. For these areas, electric heat may be the only option. Resistive electric heat is cheap to install but expensive to operate. Fuel, oil and propane is a fairly low cost option, however, have several associated hazards to be concerned with, a lot more then Natural gas.
Ground source systems work very well but very expensive to install. Geo-exchange fields can cost as much as $50,000 to install and the really tough part is when the geo-exchange field fails. The geo-exchange field should last 30-40 years but not always. We have seen a few field fail over the years and it can be devastating to a family to give this news.
With an air source heat pumps , after the units run for 20+ years, a new heat pump can be installed in a day and relatively inexpensive. A Geo-Exchange fields can take weeks to replace and it is not cheap.