Heat Recovery: How It Works How HotSpot Makes Free Hot Water HotSpot recovers concentrated high temperature heat from your compressors' condenser discharge circuit and pumps the recovered heat directly into a hot water tank. Below is a standard topology that shows the HotSpot unit connected to an existing hot water tank (pump, controls & special fittings are not shown). The HotSpot unit uses the recovered heat to keep the water temperature above the tank's thermostat set-point so that the tank heating element or burner does not need to operate.

The HotSpot recovers what is called superheat. HotSpot employs a unique desuperheater heat exchanger with a helical counter-flow design. Hot refrigerant gas from the compressor enters and flows in the opposite direction as the water flow. The water picks up the heat from the refrigerant gas, cooling the gas and heating the water. The excess heat that previously would have been thrown away by the condenser is recycled.

The HotSpot remote unit mounts outdoors (or indoors if desired) and will usually be installed on an exterior wall somewhere near the compressor. There are two pairs of inlet/outlet connections on the unit. One inlet/outlet pair is for the compressor side, the other pair is for the hot water side. Inside the unit is a small pump, sensor controls and a double helix all-copper vented double-wall heat exchanger that transfers the heat from the refrigerant (compressor side) to the hot water side. See a diagram of a standard refrigeration cycle showing HotSpot integration.

The HotSpot connects to the compressor through standard refrigeration lines, and connects to the hot water tank through standard insulated plumbing pipe, PEX etc. The pump circulates water from the tank, through the HotSpot heat exchanger, and then back to the tank. The HotSpot heat exchanger efficiently transfers the compressors high temperature waste heat to the water circuit of the unit. Dual-circuit units operate the same way, except they can connect to two adjacent compressors at the same time while connected to a single hot water tank.

For additional capacity, the tank shown above could also be configured as a "pre-heat" tank. In that type of configuration the "hot water out" (top right) would connect to the cold water inlet of the existing tank. A "two-tank" configuration allows for more recovery and more hot water capacity.

With HotSpot your compressor uses less electricity.

A significant electrical savings occurs in your system whenever HotSpot is active. When HotSpot is removing heat from a refrigeration, freezer or air conditioning compressor, the system has less work to do which reduces electrical consumption and/or increases cooling capacity.

The compressor efficiency increase occurs as the HotSpot removes the superheat from the compressor discharge circuit, which lowers the head pressure of the compressor and reduces the load on the compressor motor.

HotSpot can give a refrigeration compressor an efficiency improvement of up to 18% while extending its operating life. That means up to 18% more capacity or an 18% electrical savings, or a combination of both, while helping your compressor gain a longer service life.

Compatibility.

HotSpot is compatible with all residential and commercial refrigerants currently in use in the USA including the newer environmentally friendly refrigerants and supports, among others, R410a, R-404a, R-134a, R-22, R-500, R-502 and R-12. HotSpot works well with older and newer systems, from 10 SEER equipment up to the latest 23 SEER systems.

HotSpot includes a low-limit refrigerant temperature sensor to make sure it will never take away too much heat or over cool the refrigerant gas. It also has a high-limit sensor (prevents overheating the water) and a freeze sensor (to activate freeze protection mode).

HotSpot is compatible with all sizes of refrigeration and freezer systems from 1 ton through 100 tons including DX and packaged systems, multi-stage equipment, DC-Inverter systems and heat pumps. HotSpot is compatible with air-cooled, water-cooled and geothermal systems.

HotSpot is also compatible with local and national plumbing and electrical codes. HotSpot is tested to UL 1995 safety standards, NRTL certified, uses a double-wall vented all copper heat exchanger and meets ANSI 61/NSF potable water safety requirements.

See detailed system drawings.

Heat Recovery Unit Facts & Fiction

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