When it came to imagining the “home of the future” in the mid-20th century, builders and appliance manufacturers were all about convenience: garage doors that opened with the push of a button, electric appliances that reduced or eliminated the drudgery of housework, air conditioning that cooled an entire home via a simple wall-mounted thermostat. The focus was firmly on gadgets.
What was missing from these predictions, though, were the energy innovations to keep all these gadgets running—forwardlooking technologies to help ensure that homes of the future are efficient and affordable as well as functional.
Those technologies are playing increasingly important roles today as utilities across the country partner with innovative manufacturers to deliver a new generation of homes of the future.
Recently, the American Gas Association became a formal sponsor of the 2021–2023 Integrated Home Competition in conjunction with the Consortium for Energy Efficiency. The competition provides a platform for distinguishing innovation among a range of services, including traditional energy savings. It also encourages market adoption of home-based connected devices that provide these energy savings as well as load management, while meeting consumers’ expectations regarding interoperability, reliability and simplicity.
For 2022, the competition evaluated and awarded entries in residential connected lighting, heating and cooling; thermostats; water heating; window attachments; and more. The judges named 17 total winners, which were selected because of how they embodied the tenets of the CEE Integrated Home: energy savings, demand flexibility, consumer amenity and security.
One of those winners was Robur Corporation’s GAHP-A gas heat pump. According to the advanced heating and cooling technologies company, GAHP-A is the first air-source water-ammonia absorption heat pump on the market which, fueled by natural gas, can supply hot water up to 140 degrees Fahrenheit with a capacity of 123,500 BTU per hour.
Robur reports the pump also provides a gas efficiency, at rated conditions, of 129%. “Having a gas heat pump recognized for innovation is, I think, incredibly important to the segment as a whole, and it’s fantastic for Robur,” said Bert Warner, Robur’s North American sales and business development manager.
He added: “Quite frankly, gas is seen as a villain in a lot of markets across North America. But it doesn’t have to be that way. Gas is a viable alternative. And it’s very encouraging to be recognized for implementing gas in an effective way. The more awareness there is, the more the education grows, and the more potential customers can get a better understanding of what the advantages are.”
Warner is particularly proud of the efficiencies GAHP-A is able to attain, which he claims exceed 100%. “We can achieve numbers today that some people are projecting for 15 to 20 years from now, which is very exciting,” he said. “We’re reducing our carbon footprint and reducing emissions while still relying on natural gas, which in most markets offers more economical operating costs.”
Currently, the GAHP-A is more apt to be used in large homes, multifamily dwellings and office buildings, due to its size and weight of more than 700 pounds. However, Warner notes that Robur’s Italy-based parent company now has a residential product available in Europe that is about half the size of the North American version. “There’s a ton of interest from the true residential segment for a gas heat pump,” he said, “so Robur is currently developing a North American, 60-hertz version for this market. Unfortunately, COVID-19 essentially put a two-year hold on development. We’re now getting back on track, but I do not have an introduction date for this product at this time.”
Nonetheless, gas heat-pump technology is generating increasing interest, particularly from utilities. “The residential segment is definitely the growth pattern for the future,” Warner said. “There are a lot of meters out there, and gas heat pumps can be installed in any climate—from Vancouver to Toronto, Miami to Texas to Southern California.”
He’s optimistic about the future potential for gas heat-pump technology. “It feels like we’re at the beginning of a new wave here,” he said. “There are more manufacturers coming to play, which is tremendous; that’ll help to add credibility to the segment. And we’re seeing some strong utility support starting to happen, in terms of financial incentives and rebates that might have once been available only for high-efficiency boiler equipment in the past. Things are really starting to stage very nicely for the future growth of gas heat pumps.”
Joining that growing segment are a variety of other innovative technologies that embrace the benefits of natural gas.
For example, micro-combined heat and power systems—also known as micro-CHP—are small generators, usually less than 50 kilowatts, with the potential for residential and light commercial applications. They can be fueled by a variety of sources, including natural gas, and employ a variety of technologies, including internal combustion engines, Stirling engines, fuel cells and Rankine cycles. They can provide hydronic and warm-air space heating and/or water heating, along with grid-parallel and backup electricity. Some systems can even provide cooling.
“The key benefits of micro-CHP are resilience, greenhouse gas reduction and the opportunity for renewable integration with photovoltaic power,” said Tim Kingston, senior R&D director for building energy efficiency, GTI Energy. As a gas-technology research consultancy, GTI “has done quite a bit of research on this, and we’ve already developed strategies where we’re integrating CHP with hybrid HVAC systems—leveraging electric air-source heat pumps, hydronic heating, electric and thermal storage, and so on. We built a microgrid and nanogrid [for real-world testing] and have already hit greenhouse gas numbers below what some people are predicting for 2050.”
Because of those results, Kingston said, “I believe micro-CHP represents a tremendous opportunity for utilities to develop a new market.”
At present, though, micro-CHP is still a niche technology. Kingston cites relatively high costs, a current lack of utility support through incentives and rebates, and the need for consumer education. “At the same time, the industry is looking at future demands for resilience, efficiency and reduced greenhouse gas emissions,” he said. “That’s why we’re now seeing dozens of smallscale CHP systems either coming into the market or positioning for the market.”
Kingston notes that the main micro-CHP focus at GTI Energy has been on integration with hybrid systems, using on-site power to run air-source heat pumps in conjunction with fuel-fired hydronic heating.
“I believe hybrid systems are going to be one of the most important technologies for the future,” he said. “Solutions are unlikely to be entirely fuel-based or all-electric. The nascent electric air-source heat-pump market is coming—which offers efficiencies in certain conditions—but they are certainly less efficient than fuel-fired at lower temperatures, and they can be less comfortable. Hybrid electric/gas solutions to space conditioning and water heating will, I believe, be key for both the gas industry and the electric industry in the future.”
Kingston sees a potential tipping point for consumers and the industry: “[That] will come if the gas industry embraces micro-CHP technology, seeing it as a response to the growing demand for resilience, the expected need for alternative power sources, and the opportunity to develop a market here and build programs around it.”
He added: “I want to stress that this should not be a debate between electric utilities and gas utilities. Let’s embrace the benefits of both as they enable us to work toward energy efficiency and greenhouse gas reduction. I believe that if you do that, there will be plenty of fuel-fired equipment in the mix.”
Although a primary focus may be energy efficiency, innovative energy technologies that work together increase the potential for homes to also be energy producing. A growing number of residences—known as zero net energy, or ZNE, homes—are being built from the ground up with that goal in mind.
ZNE homes are designed to produce as much energy as they consume within a year, resulting in zero net energy consumption. They often include greater attention to insulation, improved envelope efficiency, high-efficiency appliances and the addition of solar technologies to make the home as efficient and environmentally responsible as possible.
Atmos Energy is convinced that natural gas has an integral part in the kind of low-carbon energy future that ZNE homes represent. To demonstrate proof of concept by building actual homes, the company partnered with Habitat for Humanity. Now, Atmos Energy has built seven ZNE homes that have been transferred to Habitat-sponsored homeowners, with five more homes to come, all spread across the company’s eight-state service area.
“Part of what launched this program for us was looking at greenhouse gas goals and environmental, social and governance goals nationwide and wanting to show how natural gas can be a part of achieving those goals,” said Rob Leivo, vice president of marketing for Atmos Energy’s West Texas division. “You don’t have to build an all-electric home to reach those goals. A natural gas home can be zero net energy and affordable.”
The specific ZNE features of each home, including construction choices and appliances, are developed in coordination with energy consultants, explained Darwin Stamport, vice president of marketing for Atmos Energy’s Mid-Tex division. “Any ZNE home building envelope has to be extremely tight. It has to be a lot more well insulated than what you see on your standard home,” he said. In addition, “It’s important to partner with renewables so you can offset the energy use, since a ZNE home is expected to produce as much energy as it uses. You get that from the solar and renewable sides. And then we install extremely high-efficiency natural gas appliances incorporating the latest technology, with different appliances in each of the homes, depending on the area.”
He added: “That said, I want to stress that there’s no equipment in these homes that’s uncommon or beyond what a normal, tight, energy-efficient home would be built with. We did not want these homeowners to be burdened with some piece of equipment that would cost an excessive amount of money to maintain or repair down the road.”
The response from the new homeowners has been overwhelmingly positive.
“I had the opportunity to be in Colorado on the day of dedication for the first house, which is when they turn the keys over to the new homeowners and their family,” said Leivo. “Two or three generations of the family had grown up in apartment complexes, so they were just so thankful that they had the opportunity to have a home, a safe environment to raise their kids. They couldn’t thank us enough for this project.”
The fact that these are ZNE homes is especially significant. “A lot of the folks in Habitat homes have never paid an energy bill before,” Leivo said. “They’ve lived in housing complexes where the bills are covered, so they aren’t necessarily prepared for the expense of utility bills. Energy affordability is one of the key features of these homes for these new homeowners.”
The response has been similar with the Habitat ZNE homes that have been built in Texas. “We have a home in Taylor, Texas, where the homeowner loves actually selling power back to the grid,” said Stamport. “And her electric bills are almost nothing.”
The attention garnered by the Habitat homes has generated interest from for-profit builders as well. “It’s fairly new,” Stamport said, “but the momentum is picking up as we get the message out.”
As for Atmos Energy’s initial decision to build proof-of-concept homes, Stamport said, “We can say now that it’s a very good, proven concept. So, we’d like to see it expanded, with adoption by the whole building industry, commercial as well as residential.”
Atmos Energy’s experience with ZNE homes has been particularly gratifying because it has effectively demonstrated the value of natural gas for the future—in real homes that are benefiting real homeowners.
“Sometimes electrification is the only solution being discussed,” Stamport said, “which can be misleading; natural gas plays a role as well. In fact, we don’t try to exclude any energy source. It’s partnership with all energy sources—whether it’s solar, wind, gas—that will get us to the place we need to be down the road in terms of reliability and affordability.”
“We’ve said it many times, and in front of a lot of different audiences, but an ‘all of the above’ approach really is the best solution,” Leivo added. “It’s the approach that makes use of the best that every energy source has to offer. Gas is a definite part of that. At the end of the day, energy diversity creates energy reliability and affordability.”