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Q&A Roundup : Session 3 - Beyound Heating and Cooling: Rethinking Thermal opportunities
Questions from the session Beyound Heating and Cooling: Rethinking Thermal opportunities and our consolidated responses. These reflect guidance from our technical team and focus on clear, practical explanations.
Return on Investment is always a high priority. How often, in your experience, is carbon value included in the ROI calculation. If not, why not, do you think? If so, is the valuation enough to move the needle on effective ROI?
The most straightforward way to include carbon valuation into the ROI equation is via the carbon tax, which was a primary driver in many business cases a few years ago. Unfortunately, the waiving of this tax has created ambiguity on long term policy, but some customers who are serious about decarbonization are still carrying an internal tax price into their business cases. These customers realize that the projects they are doing today will impact their facility performance for many decades to come and understand that in the long term decarbonization will yield a better return on their investment. There is also still policy at the state, provincial, or municipal levels driving decarbonization so that factors strongly into the ROIs because the cost of not meeting the carbon reduction criteria will result in fines.
Would the CO2 heat pump operate in the transcritical regime for 75 degree Celsius? Are there challenges compared to subcritical operation?
Yes the critical point for CO2 is 31 C (88F) so the system providing 75 C hot water would be operating in the transcritical region. The challenges of operating in this region are well understood because CO2 has been in mainstream use in refrigeration for over 20 years now. When operating in the supercritical region, instead of the heat being transferred to the heating medium through a condensation phase change process, the refrigerant is undergoing gas cooling which is more like a sensible heat transfer process with constant pressure but decreasing temperature as the gas cools. So at the start of heat recovery in the gas cooler there is high grade temperature of heat to recover, but at the end of the gas cooling the temperature drops substantially. The key for a heat pump application with CO2 is the return water to the gas cooler (instead of condenser) must be at a low enough temperature to recover the heat from the gas cooler outlet in order to maximize the quantity of heat recovered and COP of the CO2 heat pump. In Denmark for example, they have optimized the use of CO2 heat pumps with their district heating networks but designing the networks for this large delta T on the heating side, much more so than the district heating networks in North America. In industrial applications we have also employed gas coolers in multiple stages with CO2 for heating, with a high grade heat stage and low grade heat stage to serve multiple loads in a facility while optimizing the heating COP of the system.
Do you have third-party companies willing to pay for a project if they capture the carbon credits and partner with a non-profit?
We do not offer this service in-house, but there are many companies dedicated to working with end-users on certifying and monetizing their carbon credits, whether that’s in a mandatory or voluntary program.
These types of projects sound complicated. How would you go about technically implementing them?
From a technical standpoint these projects need a strong multi-disciplinary team, as you can see in many of these examples it’s not just a mechanical project but requires other disciplines like process and chemical engineers to be involved. We enjoy working alongside these experts and stakeholders to develop an optimized thermal system solution, and the only way to make it feasible is with a tailored approach. There are no off- the-shelf products that serve these applications we discussed today, because we need evaporators and condensers that can handle unusual working fluids or operating environments, and then they have to be coupled with the ideal compressor selections that meets the project requirements for capacity and COP.
- Note: These responses reflect guidance shared by our technical team during and immediately after the session and are intended as high‑level direction. Site‑specific engineering is required for design decisions.
Q&A Roundup : Session 2 - Deep Dive into Integrated Thermal Systems
Questions from the session Deep Dive into Integrated Thermal Systems and our consolidated responses. These reflect guidance from our technical team and focus on clear, practical explanations.
What are your thoughts on using an existing warm floor of an arena as the heat source for a heat pump? If waste heat from the ice plant is “stored” in the warm floor, what impact will this have on the cold floor?
A warm floor can technically act as thermal storage; however, most underfloor systems in ice rinks contain very little glycol and therefore have limited thermal capacity. This means the amount of heat that can be stored is quite small. If the loop were expanded—similar to a geothermal field—the thermal storage potential would increase significantly. Other in‑floor radiant heating circuits could also be used as additional storage locations.
What is the turndown ratio for the sCO₂ heat pump?
Approximately 50%, based on the Everllence design that uses a “sealed” compressor.
Can you speak about the regulatory challenges of using a river or lake as a heat source or heat sink?
Because water returned from a heat pump to a lake or river is slightly cooler than when it was extracted, it is generally not viewed as an environmental concern. Regulatory challenges are more common in cooling applications, where the water returned to the environment is warmer, which can trigger environmental impact considerations.
API‑684 defines invisible lube‑oil leakage at 6 g/hr in a seal system. How does a sealed compressor achieve zero leakage? Does this mean the unit will never require a lube‑oil refill?
The Everllence “sealed” compressor does not require any lube oil. It uses magnetic bearings and has no shaft seals, meaning no oil is present and oil leakage is impossible. For more details, search “HOFIM compressor.”
What is the smallest scale steam‑generating heat pump Everllence can produce?
The smallest system Everllence can provide is 10 MW of thermal output. CIMCO may be interested in exploring systems below 10 MW depending on project needs.
Are large hot‑water storage tanks practical as the sole reserve‑heat source in most systems?
It depends on the project. Hot‑water storage can be beneficial in many systems but not all. The key determining factor is the gap between peak heat demand and the rated heat pump capacity. This margin dictates whether thermal storage is required and how much capacity is needed.Electricity costs are expected to rise significantly with SMRs in the next 5–10 years—possibly by 82%. How does this affect heat pump economics?
Rising electrical costs strengthen the case for heat pumps, as they use far less electricity than conventional electric heating systems. Additionally, renewables such as wind can create periods of negative electricity pricing during high‑production times, allowing heat pumps to store energy economically.
Some systems are not capable of using only a heat pump. Are hybrid options feasible?
Yes. Heat pumps are often paired with other heat‑producing systems to meet total load requirements. The heat pump typically provides base‑load heating because of its high efficiency, while conventional systems serve as peak‑load or backup units.
Note: These responses reflect guidance shared by our technical team during and immediately after the session and are intended as high‑level direction. Site‑specific engineering is required for design decisions.
Q&A Roundup : Session 1 - An Introduction to Natural Refrigerant Heat Pumps
Questions from the session An Introduction to Natural Refrigerant Heat Pumps and our consolidated responses. These reflect guidance from our technical team and focus on clear, practical explanations.
When saying that natural refrigerants are more efficient than HFOs, what conditions is that assumption based on? Is there a certain lift or water‑temperature scenario? CO₂ can get pretty inefficient at higher entering heating water temperatures, correct?
This is a great question, and the nuance matters.
It’s true that CO₂ can become less efficient when rejecting heat into the outdoor ambient on a hot day, so operating conditions play a major role. In general, natural refrigerants can be more efficient than HFOs, but the conditions vary by refrigerant. Ammonia tends to excel across a wide range of temperatures because it has a very high latent heat of vaporization, which means it requires a lower mass flow for a given heat load. Its thermodynamic properties also allow it to match or exceed the efficiency of many F‑gas solutions across a broad temperature range.
Hydrocarbons show strong thermodynamic behavior as well, typically resulting in efficiencies comparable to or better than typical F‑gases. CO₂ becomes particularly efficient when the sink temperature has a high lift, in cooler ambient conditions, and in heat‑recovery scenarios.
Because CO₂ has very high fluid density, it provides excellent heat‑transfer performance and is well‑suited to systems that combine high‑ and low‑grade heat recovery. It also performs very efficiently in cooler ambient temperatures, making it a strong fit for year‑round cooling loads rather than seasonal AC demand. Typical uses include potable hot‑water heating in a transcritical water cycle and applications with multiple layers of cooling and higher‑grade heat recovery.Do you have residential heat pumps? What is the lowest temperature for these?
The capacities and design considerations in residential tend to be very small relative to our work, and the residential market often faces capacity drop‑off as temperatures fall.
There are examples of ambient‑loop systems that connect to multiple residences in a neighborhood to a central thermal network, and that helps residential heat pumps operate efficiently, our role in this type of system has been to provide the central heat pump connected to the ambient loop, rather than providing the residential heat pump itself.
With the carbon taxes removed, how can we justify pursuing low‑carbon heat‑pump technology given the potentially high capital cost?
There are viable pathways. Incentives remain important, and identifying the most viable opportunities is critical—especially those that maximize COP and leverage heat reclaim.
As a test case, we removed carbon tax from our internal heat‑pump calculator and evaluated a scenario for an Industrial Heat pump chiller replacing about 480,000 m³ of natural gas use (roughly 2,240 MBH). In that case, a 135‑ton heat pump with 247 HP compressor showed an 11‑year payback without incentives. With a maximum Enbridge incentive of about $250,000 plus other stackable incentives (e.g., an additional ~$150,000), the payback could be reduced to around seven years. More broadly, this underscores the need to target the best applications: lower lift generally yields higher COP and better economics.
Rather than chasing high‑lift, air‑source cases with marginal COP, it can be more effective to focus on heat‑recovery heat pumps—pulling from existing processes where possible—and on lower required outlet temperatures (e.g., 110°F rather than 140°F) to simplify staging and improve COP. Other drivers for decarbonization include municipal & state level decarbonization policies that still exist in many locations in North America.
Can a heat pump work without supplemental heating when the source temperature is very low? If not, won’t we still face GHG emissions from supplemental sources?
In industrial applications, it can be done if the use case is chosen carefully. As a reference point from our internal example, using readily available components, an air‑source ammonia system can be arranged for industrial space heating. With outdoor air at approximately −35°F (about −37°C) and indoor air around 90°F, the system concept produced a heating COP of about 2.9 (and about 1.9 on the cooling side). At 0°F outdoor, the heating COP would be around 3.9. These efficiencies reflect low heat‑recovery temperatures; if the target is 140°F–160°F, COP drops significantly. Also note that the simple example above did not include any losses from defrost cycles, which will reduce net COP in freezing conditions. The key is to match the application—e.g., industrial spaces that only need moderate indoor temperatures (around 50°F) can be heated efficiently even from very low outdoor air, whereas high‑temperature hot‑water requirements impose a steep efficiency penalty. A completely decarbonized district heating system would also deploy thermal storage and electric boilers, this provides the maximum flexibility to optimize the overall system performance.
It appears propane heat pumps are gaining traction in Europe.
Acknowledged. Europe is ahead of North America in the deployment of heat pumps, including natural‑refrigerant systems.
You showed very small payback periods. I assume these depend on the cost of gas and electricity—are they still realistic?
Yes—payback depends on gas and electricity prices, as well as available incentives. The specific short payback examples referenced came from feasibility studies in industrial settings and utilized waste heat, which raises COP, increases savings, and shortens payback. Those examples were from industries like wineries and breweries and were based on recovering waste heat and boosting its temperature. That drives higher COP and greater energy savings, which shortens payback.
In jurisdictions where the current spark gap already favors electrification, these cases can be viable; still, each project’s economics are site-specific
Are there air‑source heat pumps that can operate at 100% of capacity at −20°C (or lower) and still deliver a COP of ~2? Are such units commercially available?
All refrigerant‑circuit heat pumps experience capacity drop as outdoor temperature falls, so maintaining full nameplate capacity at very low ambient is generally unrealistic. It’s important to size the heat pump for the required load at the minimum design temperature.
Regarding COP ≈ 2 at −20°C: yes, this is achievable, but it depends on the heat sink temperature. For industrial heat pumps, a heating COP of 2 at −20°C is readily attainable with appropriate sink conditions; achieving this with off‑the‑shelf commercial products can be more challenging.
Are there packaged air‑to‑water heat pump solutions that integrate well with existing heating plants?
Commercial packaged options are currently more challenging and limited. For industrial applications, there are viable made‑to‑order or integrated solutions, and we routinely engineer systems to work with existing plants. Because integration depends on specifics (plant configuration, capacities, temperature requirements), the best next step is a direct discussion to assess fit and define an approach.
Among the application examples (industries, hospitals, universities, district energy), most concern large buildings. In the municipal sector we have many small/medium buildings (fire halls, police stations, libraries, arenas, aquatic centers). Are initial implementation costs higher, and is a financial ROI case needed beyond environmental benefits?
At smaller scale, natural‑refrigerant heat pumps can have higher per‑unit costs, so a clear ROI case is important. One way to improve economics is to consider district or thermal‑energy‑sharing approaches linking multiple buildings and, where possible, moving heat from where it is rejected to where it is needed (for example, reclaiming heat from an ice rink). In arenas specifically, there is both an efficiency and cost‑savings opportunity to better integrate heating and cooling. Fully integrated, all‑in‑one solutions (e.g., combining the ice‑plant refrigeration with the heat‑pump functions in a single package) can reduce intermediate heat exchangers, loops, pumping, and controls complexity, improving efficiency and lowering total installed cost while simplifying operation.
The higher efficiency you mentioned needs further justification.
We agree. Some opportunities inherently deliver better efficiencies than others. The key is to identify the cases with the best thermodynamic fit—often involving lower required heating temperatures and the use of available heat‑recovery sources—as these tend to yield higher COPs and, in turn, stronger paybacks.
Note: These responses reflect guidance shared by our technical team during and immediately after the session and are intended as high‑level direction. Site‑specific engineering is required for design decisions.
Presented by CIMCO Refrigeration
For more information, please contact cpereira@toromont.com