Ground source heat pumps

Ground source heat pumps make full use of the huge energy contained in the earth’s soil or rivers, lakes, and oceans to achieve heating and cooling of buildings. Due to the use of natural renewable free energy, the environmental protection and energy-saving effect is remarkable.

Ground source heat pump working principle:

The ground source heat pump system is a closed-loop air conditioning system composed of a double-pipe water system connecting all ground source heat pump units in the building. Below a certain depth, the underground soil temperature will be constant between 13°C and 20°C throughout the year. The heating, cooling and air-conditioning systems that use the solar energy stored on the earth as a cold and heat source for energy conversion have the characteristics of relatively stable underground normal temperature soil or groundwater temperature.

Winter: When the unit is in heating mode, the geothermal heat pump absorbs heat from soil/water, concentrates the heat from the earth through compressors and heat exchangers, and releases it indoors at a higher temperature.

Summer: When the unit is in cooling mode, the geothermal heat pump unit extracts cold energy from soil/water, concentrates the geothermal heat through compressors and heat exchangers, incorporates it into the room, and discharges the indoor heat to the room at the same time. Soil/water achieves the purpose of air conditioning.

Ground source/ geothermal heat pumps System composition

The ground source heat pump air conditioning system mainly includes the ground source heat pump unit, fan coil units, and underground pipes.

The host is a water-cooled cooling/heating unit. The unit consists of a hermetic compressor, coaxial casing (or plate) water/refrigerant heat exchanger, thermal expansion valve (or capillary expansion tube), four-way reversing valve, air side coil, fan, air filter, security control, etc.

The unit itself has a set of reversible cooling/heating devices, which is a heat pump air-conditioning unit that can be directly used for cooling/heating. A buried pipe is the part that is buried in the ground. The different buried pipes are connected in parallel and then connected to the heat pump host through different headers.

Types of Ground Source or Geothermal Heat Pump Systems

There are three basic types of ground source heat pump connecting ways. Horizontal, vertical, and ponds/lakes are closed-loop systems.

1. Horizontal connecting way of ground source heat pump unit:

This type of installation is usually the most cost-effective for residential installations, especially for new construction where sufficient land is available. It requires a trench that is at least four feet deep. The most common layouts either use two pipes, one buried at six feet and the other at four feet, or two pipes placed side by side in a two-foot-wide trench five feet underground. The Slinky annular pipe method allows more pipe to be placed in a shorter trench, reducing installation costs and enabling horizontal installation in areas not possible with traditional horizontal applications.

2. Vertical connecting way of geothermal ground source heat pumps unit:

Large commercial buildings and schools often use vertical systems because the land area required for horizontal loops can be prohibitive. Vertical loops are also used where the soil is too shallow to dig trenches, and they minimize disturbance to the existing landscape. For vertical systems, drill holes (about 4 inches in diameter) about 20 feet apart and at a depth of 100 to 400 feet. Connect the two tubes with a U-bend at the bottom to form a ring, insert into the hole, and grout for performance. The vertical loop is connected with horizontal pipes (i.e. manifolds), placed in trenches, and connected to the heat pump in the building.

3. Pond/Lake connecting way of ground source/water source heat pumps unit:

If the site has sufficient water bodies, this may be the lowest-cost option. A supply line runs underground from the building into the water and is coiled in a circle at least 8 feet below the surface to prevent freezing. Coils can only be placed in water sources that meet minimum volume, depth, and quality requirements

Ground source heat pump System Features

Traditional heat pump air conditioners face a contradiction in extracting cold and heat from the air: the hotter the weather, the hotter the air, and the more difficult it is to extract cold energy from the air; similarly, the colder the weather, the more difficult it is to extract heat from the air. Therefore, the hotter the weather, the worse the cooling effect of the air conditioner; the colder the weather, the worse the heating effect of the air conditioner, and the more electricity is consumed.

A ground source heat pump extracts cold and heats from the earth. Since the earth absorbs 47% of the solar energy, the deeper stratum can maintain a constant ground temperature all year round, which is much higher than the outdoor temperature in winter and lower than the outdoor temperature in summer, so the ground source heat pump can overcome the technical obstacle of air source heat pump, and the efficiency is greatly improved.

●High efficiency: The unit uses the renewable energy of the earth to transfer energy between the earth and the room, to provide 4-5kw of cooling or heat with 1kw of electricity. The temperature of the underground soil is constant all year round, so the cooling and heating of this system are not affected by changes in ambient temperature, and there is no heat attenuation caused by defrosting during heating, so the operating cost is low.

●Energy saving: Compared with the conventional system, the system can save 40% to 50% of the energy consumption of the house during cooling in summer, and can save up to 70% of energy consumption during heating in winter.

●Environmental protection: The ground source heat pump system does not need to be burned during operation, so it will not produce toxic gas and will not explode, which greatly reduces the emission of greenhouse gases and reduces the greenhouse effect, which is conducive to creating a green and environmentally friendly environment.

Durable: The operating conditions of the ground source heat pump system are better than that of the conventional system, so the maintenance is reduced. The system is installed indoors, not exposed to wind and rain, and can also be protected from damage, more reliable, and prolonged life; the life of the unit is more than 20 years, Underground pipes are made of polyethylene and polypropylene plastic pipes, with a lifespan of up to 50 years.

Ground source /geothermal heat pump benefit:

Ground source heat pump air conditioning systems are the most environmentally friendly and efficient cooling and heating air conditioning systems currently available. It can save more than 40% more energy than an air heat pump air conditioning system, more than 70% more energy saving than electric heating, more than 48% more efficient than a gas furnace, and the required refrigerant is more than 50% less than that of ordinary heat pump air conditioner, and 70% of ground source heat pump air conditioning system The above energy is renewable energy obtained from the earth. Some brands of units also have triple power supply technology (cooling, heating, hot water), which further realizes the most efficient comprehensive utilization of energy in the industry.