Title: +175=737.001_IK001_Brukermanual for Refra varmepumpe.Produktinformasjon.pdf
Open loop systems draw ground water directly into the building and heat/cool the heat pumps with it. The system requires sufficient ground water to meet the needs of the building. Ground water often has minerals and other contaminants in it that detrimentally affect the equipment. Open loop systems that use lake water are also available, but should use filtration equipment or secondary heat exchangers to deal with contaminates. Lake water, used in a open loop application, should be used in climates where the entering water temperature is above 4,4˚C. The ground must have the capacity to take open loop system discharge. These cannot be used below 4,4˚C without the risk of freezing. In addition, open loop systems must allow for the increased pump head from the lake/ground water level to the heat pumps. Open loop systems are not common on commercial and institutional applications and will not be covered here.