Transom Heat Pumps and the Electrification of Hot Water Systems
We recently sat down with Johan Martensson, the president and founder of Transom Corporation, to discuss heat pumps in our latest Coffee Break webinar. These bi-monthly presentations offer the most up-to-date information in the HVAC industry — ask your SVL sales engineer for an invite.
Older Heat Pump Technology
When it comes to typical air-source heat pumps, there’s a wide range of ambient temperatures in which they can operate (roughly -30 °F to 120 °F). But as the temperature drops, functionality suffers.
Recall that as the ambient temperature drops, the gas density in the loop decreases. But a compressor is a fixed-volume machine, and the reduction in gas density compels a decrease in capacity. This accounts for heat pumps’ historic poor performance in cold temperatures.
Several functions are often difficult to achieve with typical heat pumps. They must produce high temperatures for domestic hot water or new building comfort heating, and even higher temperatures to replace a gas boiler.
Transom’s Game-Changing Hatch Air Source Heat Pump
Transom researched refrigerants, compressor types, models, and manufacturers to innovate a compressor arrangement for a low-ambient, high-temperature heat pump.
The result is the Hatch Air Source Heat Pump (ASHP). Using conventional 410A refrigerant, Hatch will generate 140 °F water at -20 °F ambient temperature. It is equipped with a single- or double-wall heat exchanger and a built-in pump. It only requires front and side access (so it can be placed against a wall).
Hatch’s built-in economizer circuit means that refrigerant will be much cooler when it hits the evaporator (roughly 60–70 °F of subcooling), so it will grab much more heat out of the ambient air before it hits the compressor. This means greater capacity for less work.
Perfect for Retrofit Projects
Since Hatch heat pumps are modular, they can be added at different construction stages and pair easily with gas or electric backups. There’s a great opportunity, especially in cold climates, to install Hatch heat pumps upstream of gas boilers to reduce the load the gas backup needs to handle.
If capital is an issue, you can add more units later to increase capacity. It’s all about finding the right operational balance for your building, and modular systems allow you to adjust later as needed.
Blended Heat Pump Systems
For a balanced heating and cooling load, you can start with a dual heating and cooling water source heat pump (WSHP), and then downstream, use a Hatch ASHP (reversing heating/cooling) to take the heat from the chilled water line and create hot water.
In winter, when you need more heat than is available on the water side, the ASHP stages on as required, taking the heat out of the air and generating the high temp lead-in for the system.
In summer, when you have a mostly cooling load, the WSHP will take heat from the chilled water line and dump it into the hot water. The ASHP will switch to cooling mode, put additional cooling into the chilled water loop, and reject the heat into the air.