Rolf Bienert, managing & technical director of industry body, the OpenADR Alliance, explores the potential for HVAC systems to be energy sources rather than energy users.

Buildings are a key contributor to GHG (greenhouse gas) emissions, representing more than a third (35%) of energy related emissions in the EU, according to the European Environment Agency. These are the result of the use of fossil fuels in buildings, such as for heating, as well as the electricity consumed by devices like water heaters, air conditioning and ventilation, or HVAC for short.

While initiatives like the EU’s Energy Performance of Buildings Directive (EPBD) and the UK's first Net Zero Carbon Buildings Standard, are pushing for a reduction in the amount of carbon from buildings, are there other ways to minimise emissions and maximise energy efficiency?

Knowing that heating, cooling and hot water are responsible for anywhere between 50% (in commercial buildings) and 78% (in domestic) of energy consumption, the transition to more energy efficient systems like heat pumps will be key to success. The question, however, is whether energy hungry devices like heaters and AC systems, could in themselves become affordable, sustainable sources of energy?

As an industry alliance with many members involved in EV charging infrastructure, we have talked about the potential for electric vehicles to become grid resources.

In a vehicle to grid (V2G) or vehicle to anything (V2X) scenario, the EV acts as a mobile energy unit that can be charged ready for use, but also discharged back into the home, or the grid, and with the potential to become part of community resource with hundreds of EVs working together to form a virtual power station.

The potential for stored energy

Could the same work with HVAC? EVs have lots of stored energy and when fully charged could support a home for several days. A water heater, for example, is full of hot water when heated, so imagine the potential. With a 300-litre tank, it can store as much energy as a second-generation Tesla Powerwall, offering a cheaper way of storing large amounts of energy and providing the demand flexibility the grid needs.

Pool pumps are another example. Filtering, cleaning and circulating water means they use lots of electricity – the US Department of Energy reports that pool pumps could be the second largest energy user in the home after air conditioning or a heat pump, costing as much as $270/year in utility bills.

By combining HVAC systems in homes and buildings, we have the potential to save energy and change the way we store and consume it. New advances in HVAC is also seeing greater integration with renewables like solar and wind power, further helping us to reduce the carbon footprint.

With the potential of EVs already part of new V2X pilot schemes being rolled out by car manufacturers and utilities, why are schemes for HVAC as an energy resource not more widely tested? For a start, the right communications standards need to be in place so that electric utilities can communicate with customers and building operators.

On a positive note, the industry is now moving towards a greater focus on building management systems and interfaces that create value from appliances through improved communications. We are starting to see improved communications capabilities included in appliances like water heaters, and to monitor and learn more about energy usage. This will provide the potential for more energy efficient systems as well as utility interconnection.

We expect these systems to migrate toward EcoPort, a product certified to the CTA-2045 international standard, that allows water heaters and other HVAC appliances to communicate over the internet. Utilities can then design and deliver demand response and distributed energy programs that treat water heaters and other systems as a potential grid resource with benefits both to utilities and customers.

The utility drives demand flexibility, with peak load management or time of use programs, while customers have greater choice in their energy use together with energy and costs savings.

To see momentum in the industry as more manufacturers and utility companies demand energy smart appliances and standards-based communications is encouraging and we look forward to the next stage in development.