GCHP's on the farm

GCHP systems are being employed in a wide range of applications. Many systems have been installed in residential applications, mostly homes outside of urban areas, where there is space to install a GHX or connect to a water well. School boards started installing GCHP systems in the 1980's and '90's. The Lincoln County School Board in Nebraska has converted many of their existing schools and all new schools are designed with geothermal systems. Even a 1.5 million square foot (140,000 m2) retail shopping mall is being built with a GCHP pump system. What about applications for the technology in agricultural applications?

There is a need to store fruit and vegetables, cool and store milk, control the temperature of various products, dry grains, maintain comfortable conditions for animals and simply heat and/or cool a range of buildings and homes. Some applications GCHP systems have been used in agriculture include:

• Potato storage facility: For you to purchase potatoes in spring, potatoes must be held in a controlled environment from harvest through the winter and into spring to prevent them from spoiling. In storage, potatoes produce heat, and even during cold weather, they must be cooled. During cold weather outdoor air can be used to cool them directly, but in a warm fall and spring, cool air must be circulated through the stored potatoes.
• Dairies and milk storage: Milk must be cooled from body temperature to 38°F (4°C) within 30 minutes. When 200 or 300 cows are milked two or three times each day, a lot of refrigeration is needed to cool the milk and hold it for storage. At the same time hot water is needed to wash milking equipment and the milking parlor. Large peak cooling loads, when large volumes of milk must be cooled quickly 2 or 3 times daily, are ideal applications to use heat pumps to build ice in ice storage tanks that can be used to cool milk quickly, while at the same time, hot water can be produced in storage tanks for use in cleaning.
• Mushroom farms: mushrooms are grown in very controlled environments. There are times when cooling may be needed in once growing room, while mushrooms in another growing room may need heating. These are good applications for water to water heat pumps to provide hot and chilled water simultaneously. 
• Apple growing, processing and storage facilities: When apples are picked they must be washed and cooled as quickly as possible to maintain their quality. In the processing facilities hot water is often needed to wash the room and equipment...water can be heated using waste heat produced while cooling the apples. 
• Tree nurseries: In some tree nurseries trees are stored in a controlled environment during the winter to allow shipping for the early spring planting season. Bare root stock trees give off heat while in storage and the facilities must be cooled. Heat removed from the storage facility in winter can be used to heat other nearby buildings. A common GHX can be used to absorb heat removed from the tree storage facility, while heat pumps in nearby buildings extract heat from the same GHX. This provides a warmer heat source for the heat pumps extracting heat, while maintaining lower, more efficient temperatures for to absorb heat from the storage facility. 
• Fish farming: Nets used to hold fish in the ocean must be serviced regularly. Marine growth must be removed, nets mended and disinfected in hot water, painted with anti-fouling paint and dried. The process involves storing nets in chilled or heated water (depending on the season), cooling and reheating water to dry nets, producing hot water to disinfect them, and finally maintaining comfortable working conditions for people working in the facility. A more detailed description of a project in Newfoundland that services fishing nets can be found here.