Key factors to consider when designing carbon-neutral heating systems.
“Key challenges putting packaged heat pumps and building all electric buildings in the past has been – resistance from developer clients used to plumbing in gas, they can’t imagine a future different from the past. Since we’ve done it, it’s actually become incredibly easy.” Jeremy McLeod, Nightingale Housing.
Nightingale Heating’s experience working with Automatic Heating has highlighted how electric solutions can be accessible for many projects. For Automatic Heating, working with clients requiring a carbon neutral system for their heating hot water and space heating requirements has become commonplace in the search for sustainable solutions.
The process to design a packaged heat pump system involves consideration of multiple factors, all of which must be assessed, and each of which can impact the other. For example, the properties of different refrigerants vary, which affects both the maximum water temperature that can be produced as well as performance levels at low ambient temperatures.
Outlined below are some of these factors and how they impact on heat pump selection. For a comprehensive assessment of a specific project, we invite you to contact our technical support team.
1. Energy source
Choosing the right heat pump depending on the energy source is the primary consideration. Heat pumps can be classified based on parameters like heat source and system configuration. Among the various types of heat pumps available in the market today, however, the two types that are mainly used for heating of building interiors and domestic hot water in Australia are Air-source Heat Pumps (ASHP) and Water-source Heat Pumps (WSHP). The first step in designing an electric heating system is to determine which heat source will be used. Visit Types of Electric Heat Pumps to learn more about Air-source and Water-source heat pumps.
As mentioned above, the properties of different refrigerants vary which affects both the output temperature capacity and the heat pump’s performance under different conditions. The environmental impact of different refrigerants also varies, with natural refrigerants such as CO₂ being the most eco-friendly. CO₂ refrigerant (R744) has an ozone depletion potential (ODP) of zero and a global warming potential (GWP) of 1. Revere CO₂ Heat Pumps also achieve a high coefficient of performance (COP), which equates to significant energy savings.
Is the heating system for space heating, potable hot water, or both? Traditionally, the CO₂ heat pump was designed to produce potable hot water only. Automatic Heating, however, has successfully completed many projects that offer a heating solution for both space heating and potable water using CO₂ heat pumps. If you need both space heating and domestic hot water, it can be done!
For domestic hot water or hot water for manufacturing processes, we need to ask what is the quantity and temperature of hot water required and over what period of time? For space heating, the question is what is the area to be heated? Knowing the hot water demands and the precise area to be heated ensures the most sustainable system will be specified to provide the desired outcome without over or under specifying the system capacity.
Air source heat pumps draw their energy from the air which means performance is affected by the ambient air temperature. Knowing the intended location enables us to calculate minimum ambient temperatures and specify heat pump technology that is designed to accommodate those temperatures.