Renewable Energy with Air to Water Heat Pumps
An air to water heat pumps is a renewable option for Hydronic Slab Heating & DHW. This article will explain some of the current limitations, but if you have the right-sized system you should consider a Heat Pump for your slab heating and DHW.
Is a Heat Pump Suitable for your Hydronic Heating System?
This article aims to help you understand
- The Difference between a Hydronic Heat Pump and a DHW Heat Pump
- The limitations of Hydronic Heat Pumps
- Is your project suitable for a Hydronic Heat Pump
The Difference between a Hydronic Heat Pump and a DHW Heat Pump
To understand if your hydronic project is suitable for a heat pump, we have found the first thing a client needs to understand is the difference between a hydronic heat pump and a domestic water heat pump. This is so that you can understand just how different they are in size, upfront cost and running costs.
You see a domestic hot water heat pump is around 1kW in size. This is less than the amount of kW’s that a single large bedroom requires to heat to a comfortable temperature in winter. We find that the average Australian home requires around 20kWs. And with sophisticated technology such as heat pumps, the larger you go the more expensive they are upfront.
Another important aspect of a hydronic heat pump is that it is built and designed to operate in winter conditions at negative temperatures. Most heat pumps won’t generate hot water when the temperature gets below 5C. A Hydronic Heat Pump through its design and far higher quality parts will continue to operate efficiently to around -10C.
So size and quality parts will help explain why they are an expensive product compared to a hydronic gas boiler.
DHW with a Hydronic Air to Water Heat Pump
If your system is suitable for a Heat Pump, then you may want to consider a DHW storage system that is heated using it. These specially designed storage tanks have an inbuilt coil that the heat pump passes hot water through to heat the stored water. They heat the water much faster than a stand-alone DHW heat pump due to the size of the Hydronic Heat Pump and the huge flow rate. They are constructed using a double layer of 2205 duplex Stainless Steel making their construction far superior.
The limitations of Hydronic Heat Pumps
Hydronic Heat Pumps have limitations due to the nature of the technology and because they are an electrically powered heating system. Because a heat pump requires heat energy to raise that energy they are limited in the temperature that they will operate efficiently. As explained above, hydronic heat pumps are built of premium parts so that they can still efficiently function at -10C. As it gets colder the efficiency is greatly reduced until they can’t create heat at around -20C. Which is not going to be an issue in Australia.
In Australia, we have large homes that on average require 20kWs of heat energy. A 20kW heat pump is a very very large heat pump with a price to match. At that size, they can easily double your installation cost of a hydronic heating system and you have to consider if you’ll have enough solar power to offset your running costs enough to justify that price tag.
Heat pumps can only raise water temperatures to 50-60C which is great for slab heating. However hydronic radiator panels are designed for a water temperature of 80C. This means that the radiator panels need to be sized larger than usual.
Finally, the Heat pumps that are larger than 12kWs require 3 phase power which may not be available or desirable.
Is your project suitable for a Hydronic Heat Pump?
Hydronic Heat Pumps are a fantastic technology and it is completely up to a client whether one is the right choice for them.
Knowing the difference between domestic hot water heat pumps and hydronic heat pumps as well as their limitation we recommend using one for a small slab heating installation.
If you don’t have gas but do have solar PV and your system is 12kWs or smaller a hydronic heat pump is also going to be a smart purchase.
If your system is over 20kW a heat pump is going to double or triple your installation cost and you’d have to have a large PV system to adequately offset the running costs.
If you’d like to know how many kWs your hydronic heating system is you can get a hydronic heating quote or call us for more information 1300 303 471.