WATER-SOURCE HEAT PUMPS

A water-source heat pump (WSHP) is a system that can operate in either cooling mode or heating mode through the use of a reversing valve in the direct expansion (DX) system. An external water loop is used in a water-source heat pump to provide a means of heat transfer for the refrigerant. In an application with many different zones, such as office buildings or schools, these systems provide an effective and efficient solution to cooling and heating throughout the year. In an application where multiple water source heat pumps are used, the building loop can be used to control the temperature of the water supplied to each unit, creating a self-balancing system to reduce the need for a cooling tower or boiler.A ground source (sometimes called a geothermal) heat pump is a type of WSHP, except it uses the ground as the heat source or sink instead of the cooling tower and boiler.   

• Exceptional energy efficiency 

• Lower operating costs compared to traditional HVAC systems 

• Environmentally friendly with reduced carbon footprint 

The key difference is the heat source and heat sink in the system:

• WSHP uses a water loop that is connected to a cooling tower and boiler. 

• Ground Source (Geothermal) Heat Pump routes the water loop through the ground, leveraging stable underground temperatures. 

The maintenance for a water-source heat pump is similar to most units. Regular changes of the filters, inspection and cleaning of the coils, and checking fluid levels for the water loop are the most common forms of maintenance that will ensure proper operation and longevity of the unit. Since the unit relies on external components such as pumps, chillers, cooling towers, or boilers, these external pieces may need servicing as well to ensure proper function of the water source heat pump itself.

The initial installation costs tend to be higher than other systems, such as packaged rooftop units, primarily do to the additional installation of a an external water loop to the unit. Larger systems will add higher upfront cost as well. However, the long term savings for a water-source heat pump can create payback for the initial upfront cost over time do to the high efficiency in for cooling and especially heating for the building.

A heat pump when cooling is comparable in efficiency to other cooling equipment, but when heating they are the most efficient technology, even better than a 100% efficient electric resistance heating coil.  When multiple WSHPs are connected to a single heat pump water loop this efficiency is further enhanced because heat can be transferred between spaces decreasing or eliminating the need for the heat source or sink. 

For this reason, WSHPs are an excellent solution in commercial HVAC applications, especially as the industry progresses towards electrification.