So Hot Right Now: Innovations in Heat Pump Technology

Feb 7, 2019

Why We Need Heat Pumps

The NJ Global Warming Response Act (GWRA), which was passed in 2007, has a target requiring New Jersey to reduce GHG emissions by 80 percent from 2006 levels by 2050. This limit is equivalent to 25.4 million metric tons (MMT) CO2, or over 62 billion miles driven by an average car. According to a report by ReThink Energy NJ, the key to meeting this goal is to remove emissions created by the electric power sector, by using cleaner energy to run transportation, heating, cooling, and other systems. Energy efficient products also have a big part to play in reducing the amount  of electricity needed by homes and businesses. Electric vehicles are certainly in the sights of utilities like PSEG, as well as heat pumps, thanks to new advances in technology.


How Heat Pumps Work

Conventional heating equipment, such as gas and oil furnaces and boilers, create heat through burning fuels. Other conventional heating equipment passes electricity through a high resistance material to generate heat, a la baseboard heaters. Rather than burn fuel or heat a resistor to create heat, heat pumps instead transfer heat from one area to another, where it is needed. Nexant expert and Professional Engineer, Jason Hinsey explains that heat pumps “draw the heat from outside and ‘pump’ it into your space using systems that include refrigerants and compressors.” The system can also be reversed to pump heat away from a space, cooling the space down in the same way as a conventional air conditioning unit. There are three different types of heat pumps from the following sources:

  1. air
  2. water
  3. geothermal

Each collects heat from either the air, water, or ground and transfers it into a controlled space. Historically, the air source heat pump has been the most popular. Heat energy is present in air even when it is below freezing and a heat pump takes that energy and transfers it either in or out of the desired space in order to heat or cool the room. Because a heat pump uses electricity to transfer heat rather than burning fuel to generate heat, a heat pump is substantially more energy efficient, usually reducing electricity use around 50%.


What’s New with Heat Pumps

Although they are the most energy efficient model for heating and cooling, in the past heat pumps have not always been the most practical. Until the last few years some places were simply too hot or too cold for a heat pump to effectively regulate a home’s temperature.The dual-source options have truly been a game changer in the world of heat pumps. Now in even extreme climates a heat pump is just as proficient as a traditional heating unit while using about half the energy.

some general improvements to heat pump technology
Note: These are generalized improvements---comparing specific models would have varying results.

Our research on the latest technologies shows that heat pumps have made several advances in different areas including fan motors, refrigerants, compressors, coils, and the use of dual sources---ground and air. Dual source heat pumps (DSHP) can draw heat from either the air or the ground, depending on which is most efficient at the time, making it much more effective than traditional heat pump models. New heat pumps are also built with “dual-speed” or “variable-speed” motors to maximize comfort and electricity savings. Many of these advancements were made possible by the research of Geot€ch (Geothermal Technology for Economic Cooling and Heating), a 4-year project that worked on exploring the possibilities of high energy efficiency with lower costs, and compact “plug and play” design to appeal to the housing and small building sector.

Ground source heat pumps have long been considered too expensive to implement at a large scale, but that seems to be changing. I asked Professor Rick Greenough of De Montfort University, a contributor to the Geot€ch project, what developments could make the ground source part of the new dual pumps more cost competitive:

“Specifically one of the drivers of ground-source heat pump (GSHP) cost is the need for boreholes for installations that require the energy efficiency of a GSHP but do not have the space for shallow ‘slinky’ style heat exchangers. The cost of boreholes has always been high, but our project is demonstrating innovative rapid boring technologies that can reduce these costs. Similarly, if a customer prefers an air-source heat pump (perhaps for cost reasons) these have tended to be less efficient, hence running costs are higher than GSHP. Because electricity tends to cost around three times the price of gas (in the EU), a heat pump needs to deliver at least three times the heat per unit of electricity than a simple electric heater in order to compete with gas. Air-source units can struggle to do this, particularly in colder weather so the solution in our project is a dual-source heat pump that selects between sources in order to maximise the coefficient of performance.”

Additionally, Professor Greenough said EU legislation was a driving factor for “electrification of mobility (EVs and electric rail) and heat (heat pumps) so this will also skew prices in favour of cleaner options.”

Opportunities, Challenges, and Solutions

We see enormous opportunity, but also a few challenges to implementing these new heat pumps as a way to meet climate change goals:

  • Consumers aren’t educated about the changes in efficiency and cost, and sometimes they don’t realize heat pumps are a potential choice.
  • Utilities need robust commercial and residential programs and appealing incentives, as well as financing. These should be able to adapt as the technology develops and improves.
  • Policy makers should start advocating for subsidies, potentially concurrent with taxes on carbon emissions or other pollution metrics.
  • Manufacturers of the most cost-effective models need to be prepared for increased production.
  • Trade allies need training to sell, install, and operate the latest versions.
  • Consultants need to develop a standardized Measurement & Verification (M&V) protocol to accurately gauge success.

Some solutions to these barriers can be found by drawing a parallel to recent heat pump water heater (HPWH) programs like that of Efficiency Maine, though the technology is for heating water rather than air.

  • Use instant rebates, which are more attractive to customers and highly skilled trade allies like plumbers, and enable programs to capture more emergency replacements. In the first quarter of 2018, an instant rebate of $750 generated significant interest. But as forecasted to exceed the program budget, the instant rebate amount was reduced to $600 while the mail-in rebate stayed at $750.
  • Use a rebate level that is competitive with a baseline electric resistance water heater.
  • Simplify paperwork and provide increased incentives to trade allies to work on smaller, low-income projects, which they otherwise ignore.  

The Northwest Energy Efficiency Alliance conducted an evaluation of HPWH initiatives, which may also help future heat pump programs.

  • Create Collateral. There is a need for an informative consumer guide with pricing-related information. This will not only educate the customers in terms of the technology and retrofits but also help them interact effectively with installers and retailers.
  • Encourage installers to communicate and be the trusted source of information. Customer satisfaction rate was above 90% amongst those who purchased the HPWH. This can be improved by more effective customer-installer communications.
  • Coordinate trade allies with the new construction industry on how to transfer knowledge about heat pump installation and manufacturer incentives. This will encourage retrofit contractors to use the technology as well. Despite its initial inroads in new construction, the market share of HPWH is only about 9% of 2017 electric water heater installations (existing and new single-family and manufactured homes).

Greentech Media also reported that we have an opportunity to use load management technologies “to unlock the demand flexibility capabilities of electric heat pump water heaters and air-source heat pumps.” This would include pre-heating or pre-cooling to take load off of the peak times and potentially take advantage of solar power in the grid at the appropriate times.  

Given that this technology can be used in millions of buildings, heat pumps could easily be the next big thing in energy efficiency and electrification. We’re excited to see what happens and contribute to the conversation on their impact in commercial and residential markets.