Geothermal Heat Pumps: Cost and Installation. Installation. Before installing any new heating or cooling system in a home, it is necessary to re evaluate and reduce the energy load of the home.
A more energy efficient home will not only reduce the cost of a new system and utility bills, but it will greatly improve the comfort of your home. Before we design and install any systems, we schedule a home energy audit in which an energy auditor will recommend improvements and make estimates for cost and energy savings from these improvements. Basic improvements usually include adding insulation and air sealing measures.
Energy Environmental Corporation works with and can recommend several qualified home Energy Star auditors and installation experts. Please Contact Us for references. Geothermal heat pumps can be easily integrated with existing systems such as traditional forced air or radiant floor heating or can be installed in a new building.
Forced air systems will require a water- to- air heat pump while hydronic radiant heating systems will require water- to- water heat pumps. The size of geothermal heat pump and the size of ground loop required depends on the heating and cooling requirements for your home and is critical iin ensuring the efficiency and performance of the system. Capacity for geothermal systems is measured in tons. Typically, a 3- ton setup should suffice for the average home, but home size, heating and cooling needs, local geology and soil, and land availability are all factors which will influence the correct size for your specific home. Energy Environmental Corporation is experienced in geothermal heat pump installation and can help you properly size a system. Cost. The Economic Stimulus Recovery act of 2.
Homeowners can now receive a federal tax incentive equal to 3. See our System Pricing for more information. The design and installation of geothermal systems are not do it yourself projects and therefore require the services of a professional.
Note: Before you dive into the specific brand review, we highly recommend you to read our elaborate Heat Pump Buying Guide in advance, there are several cr.
In addition, the integration of geothermal exchange systems with other systems in a home requires special expertise. Geothermal heating system price varies depending on the type of loop system, usually either vertical or horizontal. On average, a typical home of 2. BTU and a cooling load of 6. BTU will cost between $2. This is around double the cost of a conventional heating, cooling, and hot water system, but geothermal heating/cooling systems can reduce utility bills by 4. The payback for a system can range from 2- 1.
Additionally renewable energy systems add value to the equity of your home. There are US tax rebates for energy efficiency improvements, including a 3. Visit the Database for State Incentives for Renewables and Efficiency at www. Because of the upfront cost for installing geothermal heat pump systems, it is very common to finance these systems. Monthly payments for financing a geothermal system are very reasonable and can actually save a homeowner money as soon as the system is installed.
Two examples of financing are listed below. For more information, including information on incentives and integrated systems cost, visit our web page on System Pricing. Example 1. Project Cost: $2. Rebate / Down Payment: $5,0.
Amount Financed: $2. Interest Rate: 7. Term: 2. 40 Months. Payment: $1. 66. 0. Example 2. Project Cost: $1. Rebate / Down Payment: $0. Amount Financed: $1.
Interest Rate: 8. Term: 1. 80 Months. Payment: $1. 42. 5. Back to: How Geothermal Heat Pumps Work. Types of Ground Loops.
Benefits and Efficiency of Geothermal Heat Pumps.
Geothermal heat pump - Wikipedia. This article is about using heat pumps to heat and cool buildings using the earth as a heat reservoir. For generation of electricity from genuine geothermal energy from hot rocks, see geothermal power. For using energy from hot rocks to heat directly, see geothermal heating.
A geothermal heat pump or ground source heat pump (GSHP) is a central heating and/or cooling system that transfers heat to or from the ground. It uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geosolar system with even greater efficiency. They are also known by other names, including geoexchange, earth- coupled, earth energy systems. The engineering and scientific communities prefer the terms .
The temperature in the ground below 6 metres (2. Like a refrigerator or air conditioner, these systems use a heat pump to force the transfer of heat from the ground. Heat pumps can transfer heat from a cool space to a warm space, against the natural direction of flow, or they can enhance the natural flow of heat from a warm area to a cool one. The core of the heat pump is a loop of refrigerant pumped through a vapor- compression refrigeration cycle that moves heat. Air- source heat pumps are typically more efficient at heating than pure electric heaters, even when extracting heat from cold winter air, although efficiencies begin dropping significantly as outside air temperatures drop below 5 . A ground source heat pump exchanges heat with the ground. This is much more energy- efficient because underground temperatures are more stable than air temperatures through the year.
Seasonal variations drop off with depth and disappear below 7 metres (2. Like a cave, the shallow ground temperature is warmer than the air above during the winter and cooler than the air in the summer. A ground source heat pump extracts ground heat in the winter (for heating) and transfers heat back into the ground in the summer (for cooling). Some systems are designed to operate in one mode only, heating or cooling, depending on climate. Geothermal pump systems reach fairly high coefficient of performance (Co. P), 3 to 6, on the coldest of winter nights, compared to 1. Geothermal heat pump systems are reasonably warranted by manufacturers, and their working life is estimated at 2.
Though some confusion arises when the term . After experimenting with a freezer, Robert C. Webber built the first direct exchange ground- source heat pump in the late 1. Open loop systems dominated the market until the development of polybutylene pipe in 1.
Heat can be extracted from any source, no matter how cold, but a warmer source allows higher efficiency. A ground source heat pump uses the top layer of the earth's crust as a source of heat, thus taking advantage of its seasonally moderated temperature. In the summer, the process can be reversed so the heat pump extracts heat from the building and transfers it to the ground. Transferring heat to a cooler space takes less energy, so the cooling efficiency of the heat pump gains benefits from the lower ground temperature. Ground source heat pumps employ a heat exchanger in contact with the ground or groundwater to extract or dissipate heat. This component accounts for anywhere from a fifth to half of the total system cost, and would be the most cumbersome part to repair or replace. Correctly sizing this component is necessary to assure long- term performance: the energy efficiency of the system improves with roughly 4% for every degree Celsius that is won through correct sizing, and the underground temperature balance must be maintained through proper design of the whole system.
Incorrect design can result in the system freezing after a number of years or very inefficient system performance; thus accurate system design is critical to a successful system . These temperature cycles lag behind the seasons because of thermal inertia, so the heat exchanger will harvest heat deposited by the sun several months earlier, while being weighed down in late winter and spring, due to accumulated winter cold. Deep vertical systems 1. Several major design options are available for these, which are classified by fluid and layout.
Direct exchange systems circulate refrigerant underground, closed loop systems use a mixture of anti- freeze and water, and open loop systems use natural groundwater. Direct exchange (DX). The ground- coupling is achieved through a single loop, circulating refrigerant, in direct thermal contact with the ground (as opposed to a combination of a refrigerant loop and a water loop). The refrigerant leaves the heat pump cabinet, circulates through a loop of copper tube buried underground, and exchanges heat with the ground before returning to the pump.
There is no direct interaction between the fluid and the earth; only heat transfer through the pipe wall. Direct exchange heat pumps are not to be confused with . ASHRAE defines the term ground- coupled heat pump to encompass closed loop and direct exchange systems, while excluding open loops. Copper's high thermal conductivity contributes to the higher efficiency of the system, but heat flow is predominantly limited by the thermal conductivity of the ground, not the pipe. The main reasons for the higher efficiency are the elimination of the water pump (which uses electricity), the elimination of the water- to- refrigerant heat exchanger (which is a source of heat losses), and most importantly, the latent heat phase change of the refrigerant in the ground itself. However, in case of leakage there is virtually no risk of contaminating the ground or the ground water.
Contrary to water- source geothermal systems, direct exchange systems do not contain antifreeze. So, in case of a refrigerant leakage, the refrigerant currently used in most systems - R- 4.
A – would immediately vaporize and seek the atmosphere. This is due to the low boiling point of R- 4. A: - 6. 0. 5 . R- 4. A refrigerant replaces larger volumes of antifreeze mixtures used in water- source geothermal systems and presents no threat to aquifers or to the ground itself. While they require more refrigerant and their tubing is more expensive per foot, a direct exchange earth loop is shorter than a closed water loop for a given capacity. A direct exchange system requires only 1.
Refrigerant loops are less tolerant of leaks than water loops because gas can leak out through smaller imperfections. This dictates the use of brazed copper tubing, even though the pressures are similar to water loops.
The copper loop must be protected from corrosion in acidic soil through the use of a sacrificial anode or other cathodic protection. The U. S. Environmental Protection Agency conducted field monitoring of a direct geoexchange heat pump water heating system in a commercial application. The EPA reported that the system saved 7. According to the EPA, if the system is operated to capacity, it can avoid the emission of up to 7,1.
CO2 and 1. 5 pounds of NOx each year per ton of compressor capacity (or 4. Any temperature above - 4. The secondary loop is typically made of high- density polyethylene pipe and contains a mixture of water and anti- freeze (propylene glycol, denatured alcohol or methanol). Monopropylene glycol has the least damaging potential when it might leak into the ground, and is therefore the only allowed anti- freeze in ground sources in an increasing number of European countries. After leaving the internal heat exchanger, the water flows through the secondary loop outside the building to exchange heat with the ground before returning. The secondary loop is placed below the frost line where the temperature is more stable, or preferably submerged in a body of water if available.
Systems in wet ground or in water are generally more efficient than drier ground loops since water conducts and stores heat better than solids in sand or soil. If the ground is naturally dry, soaker hoses may be buried with the ground loop to keep it wet. Some manufacturers have a separate ground loop fluid pump pack, while some integrate the pumping and valving within the heat pump. Expansion tanks and pressure relief valves may be installed on the heated fluid side. Closed loop systems have lower efficiency than direct exchange systems, so they require longer and larger pipe to be placed in the ground, increasing excavation costs. Closed loop tubing can be installed horizontally as a loop field in trenches or vertically as a series of long U- shapes in wells (see below). The size of the loop field depends on the soil type and moisture content, the average ground temperature and the heat loss and or gain characteristics of the building being conditioned.
A rough approximation of the initial soil temperature is the average daily temperature for the region. Vertical. A hole is bored in the ground, typically 5. Pipe pairs in the hole are joined with a U- shaped cross connector at the bottom of the hole. The borehole is commonly filled with a bentonitegrout surrounding the pipe to provide a thermal connection to the surrounding soil or rock to improve the heat transfer. Thermally enhanced grouts are available to improve this heat transfer. Grout also protects the ground water from contamination, and prevents artesian wells from flooding the property.
Vertical loop fields are typically used when there is a limited area of land available. Bore holes are spaced at least 5–6 m apart and the depth depends on ground and building characteristics. For illustration, a detached house needing 1. W (3 ton) of heating capacity might need three boreholes 8. Reliable heat transfer models have been developed through sample bore holes as well as other tests. Horizontal. The three slinky loops are running out horizontally with three straight lines returning the end of the slinky coil to the heat pump.