Just a quick note as to my qualifications; I was a refrigeration engineer and have designed various refrigeration systems from commercial refrigeration applications for the grocery and food service industry and ULT(Ultra Low Temperature) systems designed to achieve temperatures as low as -80C/-112F.

The logic here is a bit flawed. It assumes that the only method of cooling the refrigerant would be the water in the hot water reservoir. Here in the US this is a hot water tank/heater.

In reality the most optimum way of achieving energy savings is to use a separate pump to circulate water from the tank to what is known as a water cooled condenser for the AC system. This water cooled condenser s in series with the current air cooled condenser. Once the water achieves a predetermined temperature the pump could be turned off and the hot refrigerant/freon gas would continue on to the air cooled condenser which would perform its normal function of cooling the refrigerant/freon. The normal heaters in the hot water tank would or could then be used to bring the water up to the 60C or 140F temperature to combat legionella if required. Here in the USA this is a rare issue. Other ways to aid in reducing the legionella contamination are as follows

1. Use copper pipe in the water lines used to connect the system.
2. Typical chlorination of the water also aids in preventing this.
3. Do not use open air Cisterns. Our systems in the USA do not use open air cisterns for the water storage.
4. Install a UV light system in the water lines to offer additional protection. Currently my personal hot water heaters are only set to approximately 110F/43C in an effort to reduce the energy required.

Because you would run the refrigerant/freon discharge from the compressor thru the water cooled condenser prior to the reversing valve in a heat pump application the water potion of the system could reside very close to the HVAC system even in the winter which would prevent the water from freezing and make the system viable even in the winter. One could also install a safety switch that would activate the pump in the event that the water temperature drops below a predetermined point to protect from freezing.

If you would be interested in this please respond and if there is sufficient interest I may put together a more informative site or page. Thanks

Just a quick note as to my qualifications; I was a refrigeration engineer and have designed various refrigeration systems from commercial refrigeration applications for the grocery and food service industry and ULT(Ultra Low Temperature) systems designed to achieve temperatures as low as -80C/-112F.

The logic here is a bit flawed. It assumes that the only method of cooling the refrigerant would be the water in the hot water reservoir. Here in the US this is a hot water tank/heater.

In reality the most optimum way of achieving energy savings is to use a separate pump to circulate water from the tank to what is known as a water cooled condenser for the AC system. This water cooled condenser s in series with the current air cooled condenser. Once the water achieves a predetermined temperature the pump could be turned off and the hot refrigerant/freon gas would continue on to the air cooled condenser which would perform its normal function of cooling the refrigerant/freon. The normal heaters in the hot water tank would or could then be used to bring the water up to the 60C or 140F temperature to combat legionella if required. Here in the USA this is a rare issue. Other ways to aid in reducing the legionella contamination are as follows

1. Use copper pipe in the water lines used to connect the system.
2. Typical chlorination of the water also aids in preventing this.
3. Do not use open air Cisterns. Our systems in the USA do not use open air cisterns for the water storage.
4. Install a UV light system in the water lines to offer additional protection. Currently my personal hot water heaters are only set to approximately 110F/43C in an effort to reduce the energy required.

Because you would run the refrigerant/freon discharge from the compressor thru the water cooled condenser prior to the reversing valve in a heat pump application the water portion of the system could reside very close to the HVAC system even in the winter which would prevent the water from freezing and make the system viable even in the winter. One could also install a safety switch that would activate the pump in the event that the water temperature drops below a predetermined point to protect from freezing.

If you would be interested in this please respond and if there is sufficient interest I may put together a more informative site or page. Thanks

p.s. I clicked on the link at the top of the page for the Hotspot Energy Recovery systems and this is exactly what I was describing above. I do not know about pricing, however they do offer a savings calculator on their website, however it is logically flawed as it assumes that you are using all of the hot water you could potentially make and this is just not the case. The issue with this product is that the installation of such would be very expensive to have an HVAC contractor install this, unless you could convince them to do so if you were having a new system installed and then I am unaware of the cost of such a system.