The EarthLinked® system has three major components:
An earth loop system that circulates a heat transfer refrigerant to exchange heat with the earth.
A heat pump that moves heat or cool between the building and the earth via the earth loops.
A distribution system to distribute comfort throughout the building.
And two options for water heating:
A desuperheater to capture waste heat from the air conditioning cycle and move it to the water heater.
A full-demand water heater, where the EarthLinked system supplies all of your hot water needs year-around.
Earth Loop System - engineered for efficiency and flexibility
The earth loops are like arteries in a human body. The loops are connected to the heat pump to circulate refrigerant and directly exchange thermal energy with the earth. EarthLinked ground loops have the smallest size and smallest footprint in the market. They have the highest temperature differential with the earth, which means they can use the least amount of earth contact to work effectively. The loops can be installed in three different configurations—horizontal, vertical or diagonal—for maximum design flexibility and cost-effectiveness.
The long-lasting earth loops are made of copper, one of the few metals that exist naturally as an element in the earth. A noble metal, copper resists corrosion because of the protective film that forms naturally on its surface. In rare exceptions where pH readings exceed safe levels, we offer the proprietary Cathodic Protection System for the in-ground copper to preclude corrosion in harsh conditions. With installations dating back to 1980, we have never experienced a field failure of a production earth loop due to corrosion.
The earth loops are pre-assembled and pressure-tested for maximum convenience, quality, and easy installation. Depending upon underground conditions, loops using vertical or diagonal configurations are typically installed in less than two days, whereas horizontal loops can be installed in a single day.
Heat Pump - the heart of the system
Like a pulsing heart, the heat pump circulates the refrigerant through the earth loops to exchange thermal energy with the earth. No complex digital or mechanical equipment is required. Just three mechanically simple devices (a compressor, a condenser and an evaporator) enclosed in a small indoor unit and integrated to work seamlessly, leveraging the natural laws of physics. The system is more reliable and efficient than other geothermal systems because it has no water circulating pump, intermediate heat exchanger or thermostatic expansion valve.
The heat pump is engineered for easy integration with the building’s heat distribution system. Because the unit is fully enclosed, it can be installed indoors and does not have to withstand the stress of extreme temperature changes and inclement weather.
Refrigerant Flow Controls
A uniquely innovative, patented technique enables control of the flow and stability of the refrigerant without any electronic devices, thereby further improving the efficiency and reliability of the EarthLinked system. The refrigerant is efficiently managed by two simple proprietary flow control devices: the Active Charge Control and Liquid Flow Control.
These two mechanical controls respond directly to the temperature and velocity of refrigerant flow through the system. They modulate the amount of refrigerant in circulation to assure optimum efficiency at all times. By eliminating subcooling in the condenser, the system operates at lower refrigerant "head" pressures with increased mass flow, which reduces energy consumption, increases heat transfer, system reliability and useful life.
Depending on site conditions, an EarthLinked system can be installed in one to two days. Once the appropriate system capacity is identified, the following steps are taken:
Choosing the appropriate loop configuration. Earth loops can be installed in vertical, diagonal or horizontal configurations to provide the lowest cost method, depending upon space availability. The design options are flexible to adapt to site conditions and available space.
Drilling for space efficiency. Depending on the loop configurations chosen, holes are drilled in the ground or installed horizontally in the excavated space.
The copper loops. After the holes are drilled or excavated, the earth-loops are inserted. These loops circulate the refrigerant continuously from the earth loop field to the heat pump and distribution equipment in the building. Once the loops are installed, the holes are grouted to assure good earth contact and no voids.
Connecting the earth loops to the manifold. All of the loops are joined either to the supply or return manifold where the earth loops converge, channeling refrigerant through the lines that are connected to the compressor.
The role of the compressor. The refrigerant lines are connected to the compressor, which increases the pressure and temperature of the refrigerant. Heat energy released by the pressurized refrigerant may be channeled either to the building if heat is needed or to the earth if cooling is needed. The process is controlled by a thermostat and a reversing-valve.
Connecting an air handler. The refrigerant line may then be run from the compressor to an air handler. The air handler is used to transfer heat from the refrigerant to the air and circulate the heated air in the building, or to remove it from the building in summer by exchanging it from the circulating air into the refrigerant line for transport to the earth.
Connecting a radiant hydronic system. In the alternative, the refrigerant line may be run from the compressor to a refrigerant-to-water heat exchanger that is used to transfer heat into a hot water circulating system to heat the building.
Heating Mode Specifics
In the heating mode, the refrigerant enters the earth loops as a cold liquid (blue in the graphic) and comes out as a cool vapor (green in the graphic). When a refrigerant evaporates it absorbs a large quantity of heat from any surrounding material.
Therefore as the refrigerant flows through the loops, it absorbs heat from the earth and stores it in vapor form for later release. The cool (green) vapor that is heat-charged after leaving the earth loops then enters the compressor where its temperature is raised from about 40°F to about 160°F.
During this compression stage, the temperature of the vapor increases because of the intense compression and the vapor leaves the compressor (red in the graphic) hotter than the air in the building being heated. Because the vapor leaving the compressor that is hotter than the inside air, heat transfers into the air flow as the air passes the fan coil in the air handler. This warms your home.
As the heat is removed while the hot vapor passes through the condenser, the vapor condenses and exits the condenser as a liquid. This warm liquid (yellow in the graphic) enters the flow control unit, which monitors the amount of vapor arriving at the liquid flow control (LFC), and meters liquid only through the device for its return to the earth loop field.
Cooling Mode Specifics
In the cooling mode, cool vapor (green in the graphic) arrives at the compressor after absorbing heat from the air in the building. The compressor compresses the cool vapor into a smaller volume, increasing its heat density.
The refrigerant exits the compressor as a hot vapor (red in the graphic) which then goes into the earth loop field. The loops act as a condenser condensing the vapor until it is virtually all liquid. The refrigerant leaves the earth loops as a warm liquid (yellow in the graphic).
The flow control regulates the flow from the condenser so that only liquid refrigerant passes through the control. The refrigerant expands as it exits the flow control and becomes a cold liquid (blue in the graphic). Because the liquid evaporates as it passes through the cooling coil located in the air handler, it absorbs heat from the air blowing over the coil surface and thus cools your home.
