Commercial Heat Pump Hot Water Systems

• Commercial heat pumps for hot water can be used in commercial buildings and apartment buildings with centralised hot water systems. However, if replacing a gas system, the location and number of hot water heaters required may differ from the original installation.
• The location of the hot water plant may need to be moved to an external location.
• Commercial kitchens require hot water at 77°C. Heat pumps cannot reach these temperatures. Therefore, an alternative hot water system to a heat pump will be required for commercial kitchens.
• The temperature of return hot water throughout a domestic hot water circulating loop must be a minimum of 55°C to prevent the growth of legionella bacteria. All hot water flow and return pipes will need to be sufficiently insulated.
• To match the output of existing gas hot water systems, heat pumps may be required to work almost continuously.
• To match the output of existing gas hot water systems buffer tanks may be required to cope with periods of peak hot water demand.
• When replacing gas systems, new wiring may need to be installed between the meter board and the hot water plant room.

Like domestic heat pumps, heat pumps for commercial hot water use refrigerant principles (Joules Thompson Effect ) and refrigerant gases to extract heat from an external heat source. The heat is then transferred from the refrigerant gas into a tank filled with water via an inbuilt heat exchanger.

Joules Thomson Effect is the change in a gas’s temperature, becomes endothermic - feels cold, as it flows from a higher-pressure region to lower-pressure region, and becomes exothermic - feels hot, when undergoing a pressure rise as it flows from a lower-pressure region to a higher-pressure region.

1. Ground source heat pumps/ Geothermal Heat pumps / Water to Water

The external heat source comes from the ground via a closed loop water pipe. The heat in the ground in the Canberra region at 1.5meters deep remains constant at approximately 15 -18°C. The closed loop water pipes may be laid in horizontal trenches or in deep vertical shafts.

2. Air source heat pumps / Aerothermal heat pumps / Air to Water.

The external heat source comes from the surrounding air. Although we think of 0°C as freezing, there is enough heat left in the air for a good Aerothermal heat pump to extract sufficient heat at air temperatures as low as -10°C.

3. Combination Air to Water – Water to Water

Using the same principles as standard heat pumps, combination Aerothermal - Geothermal hot water heat pumps have the highest all year round Coefficient Of Performance (COP) of around 4. meaning that the heating output is 4 times as great as the power input, or a year round efficiency of 400%.

Using smart technology, they can switch from air to ground heat extraction, depending on the external air temperature, ground temperature and heating or cooling requirements.

• Hot water return temperature in circulating loops must be above 55°C to prevent legionella bacteria growing in hot water piping systems. This may require continual heat pump operation.
• Heat pumps cannot respond to periods of peak hot water demand like gas hot water systems can, especially in cooler seasons. Therefore, hot water buffer tanks may be required.
• As far as we are aware, no heat pump can meet AS/NZS food standards requirements for hot water temperatures of 77°C for commercial kitchens.
• Retrofitting commercial heat pumps for hot water may be ten – twenty times the cost of their gas equivalents.
• The space requirements of commercial hot water heat pumps may be up to twenty times that of an equivalent commercial gas hot water system.

• The ACT government wants to phase out distributed fossil fuel gas in Canberra by 2045 and distributed green hydrogen won’t be available in Canberra until sometime between 2028 – 2033- if at all.
• Existing natural gas appliances will not operate with pure hydrogen or hydrogen blended into the networks at concentrations above 10% to 20%. If distributed green hydrogen occurs in Canberra, existing gas appliances will need to be replaced.
• The ACT government’s no fossil fuel gas policy is already causing a large number of existing gas customers to disconnect from the gas network. Because network operating costs will remain constant or increase, despite the number of customers connected to it, these costs have to be spread among fewer gas customers. This increases the cost for those staying with gas.
• Natural gas prices are also increasing, and it is expected that the cost of distributed green hydrogen will be higher than the cost of natural gas, at least in the initial stages.
• Combustion of natural gas emits CO2.
• Commercial heat pumps should be less expensive to operate than gas hot water systems.

We do install commercial solar hot water systems, but our experience says no.

• Commercial solar hot water systems can require very complex control systems and they are costly to maintain and repair.
• When the sun does not shine, their electric booster elements draw a significant amount of power to produce hot water. When boosting, the electrical load can be as much as 400% higher than the electrical load of an equivalent heat pump.
• Because return water in a hot water circulating loop must be above 55°C solar hot water heaters can lose their stored solar hot water very quickly when the sun goes down. Therefore, the cost of electric boosting at night would be significant.
• Large buffer tanks would be required to cope with periods of peak demand, usually mornings and evenings. This adds to installation costs and space requirements.
• Solar hot water systems are more easily damaged in weather events than heat pumps are. This adds to long term costs of ownership.
• Solar hot water systems are typically more expensive to maintain than heat pumps hot water systems.
• The local electricity network and the inlet service to the apartment building may not be able to carry the amount of power required for electric boosting of solar hot water heater systems when required. Upgrades to electricity networks, inlet services and internal wiring are mind bogglingly expensive.
• Solar hot water collectors for commercial applications require a lot of roof space that could otherwise be used for the generation of green electricity.

Regardless, commercial solar hot water may be the best option for transitioning away from gas for hot water. If your building is in Canberra, for a modest fee, our hot water technicians can determine the best way to help you transition off gas.

Find out more about commercial solar hot water systems.

We install instantaneous / continuous flow electric hot water systems. Rarely are they suitable alternatives to existing centralised hot water systems, gas continuous flow hot water systems or heat pumps for hot water.

• Single phase 240 volt instant hot water systems do not provide enough hot water for a shower. They are suited to low volume fixtures like sinks and hand basins only.
• Each three phase electric continuous flow hot water system requires 415 volt 3 phase wiring. This can be mind boggling expensive to retrofit into an existing apartment and apartment building.
• The local electricity network and the inlet service to the apartment building may not be able to carry the amount of power required for single phase and electric 3 phase instantaneous hot water systems during peak periods. Upgrades to electricity networks and inlet services are also mind bogglingly expensive.
• Instantaneous electric hot water heaters tend to have a short life in Canberra.
• Instantaneous electric hot water heaters can not be installed in external locations.
• Large capacity electric continuous flow hot water systems that produce the same volumes of hot water as commercial gas hot water systems do not exist.

Regardless, instantaneous electric hot water may be the best option for transitioning away from gas for hot water. If your building is in Canberra, for a modest fee, our technicians can determine the best way to help you transition off gas.
Find out more about electric continuous flow / instantaneous electric hot water systems.

There are two ways electric storage hot water systems can be used in apartment buildings. These are:

1. Centralised commercial electric storage hot water

For centralised hot water, electric storage systems are generally not suited to apartment buildings when transitioning from centralised gas hot water systems.

• The local electricity network, the inlet service to the apartment building and internal wiring may not be able to carry the amount of power required for electric storage hot water heaters. Upgrades to electricity networks, inlet services and internal wiring are mind bogglingly expensive.
• Because return water in a hot water circulating loop must be above 55°C electric storage hot water systems may need to heat constantly. Power bills for hot water would be very high.
• Additional buffer tanks would be required to cope with periods of high demand. (normally mornings and evenings) This adds to installation costs.
• The life of the electric storage tanks would likely be double that of heat pumps.
• The installation costs of centralized commercial electric storage tanks would be 50% lower than centralised commercial heat pump installations.
• The space requirements for centralised electric storage systems would be significantly greater then the space required for existing commercial gas hot water systems.

Regardless, a centralised electric hot water storage system may be the best option for transitioning away from gas for hot water. If your building is in Canberra, for a modest fee, our technicians can determine the best way to help you transition away from gas.

Find out more about electric storage systems visit:

Rheem Commercial Electric Systems
- https://rheem.com.au/rheem/products/Commercial/Commercial-Electric/c/commercial-electric

2. Decentralised electric storage hot water

For decentralised hot water, electric storage hot water systems may be better than commercial heat pumps, when transitioning away from decentralised and centralised gas hot water systems.

• Electric storage hot water systems installed inside each apartment would require new internal wiring in the apartment. This may prove very expensive in single level and multi-story buildings.
• The local electricity network, the inlet service to the apartment building and internal wiring may not be able to carry the amount of power required for electric storage hot water heaters. Upgrades to electricity networks, inlet services and internal wiring are mind bogglingly expensive.
• Storage tanks would require a space of 600mm D x 700mm W and 1200 -1900 mm H.
• Electric storage hot water heaters can be installed internally and externally. This may provide more installation options than for heat pumps.
• New plumbing would need to be connected between the existing hot and cold pipes and the hot water tank.
• Existing plant rooms could be decommissioned, and the space used for other purposes.
• The cost of maintaining common property hot water heaters, main flow and return piping systems and pump systems would no longer be the responsibility of body corporates.

Regardless a of any downsides, decentralised electric hot water storage systems may be the best option for transitioning away from gas for hot water. If your building is in Canberra, for a modest fee, our experienced tradespeople can determine the easiest path to help you transition away from gas.

Find out more about electric storage systems

When transitioning from a centralised gas hot water system, decentralised domestic heat pump hot water heaters are not likely better than a centralized commercial heat pump installation.

• Compact storage tanks would require a space of 600mm D x 1500mm W and 1800 -2000 mm H. Compact heat pumps should not be installed in corners.
• Compact heat pumps can be very heavy, weighing between 250kgs and 400 kgs when full. This may effect the structural integrity of internal and external flooring systems.
• In some cases, split system heat pumps may be a better option than compact heat pumps.
• Hot water systems installed on balconies for each apartment would require new internal wiring in the apartment. This may prove very expensive in single and multi-story buildings.
• New plumbing would need to be connected between the existing hot and cold pipes and the heat pump hot water tank.
• Split system domestic heat pumps, with the storage tank inside and the condenser outside, would likely cost twice as much as an external compact heat pump to install.
• The cost of maintaining common property hot water heaters, main flow and return piping systems and pump systems would no longer be the responsibility of body corporates.

Regardless of any downsides, a decentralised domestic heat pump hot water system may be the best option for transitioning away from gas for hot water. If your building is in Canberra, for a modest fee, our experienced tradespeople can determine the easiest path to help you transition away from fossil fuel gas.

Find out more about domestic heat pump hot water heaters: