Dual fuel heat pump packaged rooftop units (RTUs) offer a versatile and energy-efficient solution for heating and cooling commercial buildings. By combining the efficiency of a heat pump with the power of a gas furnace, these units provide optimal comfort and performance in various climates.

Heat pumps have a lot of benefits for the climate and performance.  They also have some challenges around efficiency at cold temperatures, and there are concerns about grid performance if and when a lot of heat pumps and trying to heat at the same time.  

Dual fuel heat pumps are the best of both worlds – maximum performance, and then back up natural gas or electric resistance heat below a certain temperature.  In this article, we will explore more as well as discuss a pilot program from our local utility to study and explore these new heat pumps. 

What are the Benefits of Dual Fuel Heat Pump RTUs?

One of the primary benefits of dual fuel RTUs is their enhanced energy efficiency. During mild weather conditions, the heat pump can effectively heat and cool the building, reducing reliance on the gas furnace. This results in lower energy consumption and reduced utility bills. Additionally, the gas furnace can provide backup heat during extremely cold temperatures, ensuring consistent comfort even in harsh conditions.

Another advantage of dual fuel RTUs is their flexibility and adaptability. These units can be customized to meet the specific needs of different building types and sizes, making them suitable for a wide range of commercial applications. Moreover, dual fuel RTUs often incorporate advanced technology, such as variable-speed fans and intelligent controls, to optimize performance and minimize noise levels.

Finally, dual fuel RTUs can contribute to a more sustainable and environmentally friendly future. By reducing reliance on fossil fuels and increasing energy efficiency, these units can help to lower greenhouse gas emissions and promote a healthier planet.

How is the Efficiency of HVAC Measured?

In the realm of Heating, Ventilation, and Air Conditioning (HVAC), COP is a crucial metric used to assess the efficiency of equipment, particularly heat pumps. COP, which stands for Coefficient of Performance, quantifies how effectively a system converts energy input into useful output.

A higher COP value indicates a more efficient system. For heat pumps, the COP is calculated by dividing the heat delivered to the space by the electrical energy consumed. This means that a heat pump with a COP of 3 delivers three units of heat for every one unit of electricity used.

Several factors influence a heat pump’s COP, including the outdoor temperature, the system’s design, and proper installation and maintenance. Generally, heat pumps operate more efficiently in milder climates, as they can draw heat from the outside air more effectively. Additionally, well-maintained systems with advanced technologies like inverter compressors can achieve higher COPs.

Understanding COP is essential for making informed decisions when selecting HVAC equipment. By choosing a system with a high COP, you can reduce energy consumption, lower utility bills, and minimize your environmental impact.

What is the COP of a Heat Pump?

A heat pump’s Coefficient of Performance is a measure of its efficiency in converting electrical energy into heat. While heat pumps are generally more energy-efficient than traditional furnaces, their COP can decrease as outdoor temperatures drop.  Above freezing temperatures, the COP of a heat pump can be 3.5 to 4.0, which is incredibly high.  In fact, another way of saying this is that heat pumps are 350% to 400% more efficient than traditional sources likely in place in your building now. However, below freezing, the COP can drop and get closer to traditional means of heating. 

The primary reason for the decline at cold temperatures is the increased difficulty in extracting heat from the colder air. As the temperature decreases, the heat pump’s evaporator coil struggles to absorb enough heat from the outside environment. This reduced heat absorption can lead to a decrease in the overall efficiency of the system.

Additionally, colder temperatures can also increase the frequency of defrost cycles. During defrost, the heat pump’s evaporator coil is heated to remove frost buildup, which can temporarily reduce its heating capacity and increase energy consumption.

However, it’s important to note that modern heat pump technologies have made significant strides in improving their performance at lower temperatures. Many newer models incorporate features such as inverter compressors and advanced defrost controls to help maintain a higher COP even in colder climates.

These gains are typically seen in Variable Refrigerant Flow systems, which are more ideal for a commercial building if budget is not a concern.  However, while they perform much better in modern days than the previous generation  of heat pumps, they still involve a lot of construction and changing of the design of the system.

For those buildings that have limited budget, a dual fuel heat pump system combines the benefits – great COP and efficiency 90% of the year, with natural gas or electric back up on those days that are way below freezing.  

What is better as a backup to a heat pump, natural gas or electric resistance?

When considering heating options for a home or commercial building, efficiency is a crucial factor. Natural gas and electric resistance heating systems have distinct characteristics in terms of COP.

Electric resistance heating systems are relatively simple in design. They convert electrical energy directly into heat by passing a current through resistive elements. While these systems are easy to install and maintain, they have a lower COP compared to natural gas heating. This is because they convert all the electrical energy into heat, without any intermediate steps.

Natural gas heating systems, on the other hand, utilize a combustion process to generate heat. Natural gas is burned in a furnace or boiler, releasing heat that is then transferred to the living space. Due to this process, natural gas heating systems can achieve higher COPs than electric resistance heating. This is because the combustion process is more efficient in converting the energy in natural gas into heat.

However, the COP of a natural gas heating system can vary depending on factors such as the efficiency of the furnace or boiler, the quality of the installation, and the local climate. Older or poorly maintained systems may have lower COPs. Additionally, the efficiency of natural gas heating can be affected by factors like the quality of the natural gas itself and the altitude of the location.  Traditional packaged RTUs have an 80% efficiency by design, so the COP is never going to exceed 0.8.  

Electric resistance is in theory a 1.0, since all of the energy that goes in is converted into heat.  While the COP may be higher than natural gas, the cost may also be higher as electricity tends to be more expensive at similar COPs than natural gas in our current environment in 2024 in Illinois.  That may change in the future, but for now, we recommend natural gas as a backup for several reasons.

Why Do We Recommend Natural Gas as a Backup instead of Electric Resistance Heating?

There are three main reasons – grid stability, costs, and existing natural gas lines.

When it is very cold out, especially when a polar vortex occurs, we have seen both some concerns around our grid as well as temporarily higher costs for electricity.  For now, using natural gas during those times seems the most logical.

Natural gas is also very inexpensive in Illinois compared to other states and regions.  While that may not maintain into the future, the moment makes this an important consideration for Return on Investment and Payback – both critical decision points.

Finally, if your building already has natural gas lines to your current packaged RTU, keeping those lines in place is easy and affordable (as opposed to running new lines).  There are reasons to remove all of the natural gas costs to a building, including removing the expensive monthly fee for service.  But you must also remove all of the cooking equipment, water heating and heating sources for an entire building, which can be an expensive undertaking.  

What Are Next Steps?

If this is appealing to you, and you have a packaged RTU that is over 10 years old, the first step is to set up an energy efficiency assessment for your building. It is important to look at a building as a whole vs just one component.  

In fact, in 2024 and 2025, our local utility company (Comed) has a pilot program through the Center for Energy and the Environment that is incredibly generous to explore this new technology.  It could cover a lot of the cost for those interested in making this kind of transition – higher incentives than we have ever seen on packaged HVAC units.  Those higher incentives will come with some interviews and data collection – but our experience has been that those are more than worth it. 

 

Traditional Heat Pumps use refrigerant to change stages based on pressure, transferring heat from inside a building and out (and vice versa in the winter). One of the big costs to heat pumps is Freon, which is expensive, as well as the copper lines running through a building to transfer the heat around via Freon.

There is a new technology breaking that uses CO2 to act as the refrigerant. It is exciting, and we will discuss some reasons it may or may not break out into the US anytime soon.

A Very High Efficiency HVAC system has an air sourced heat pump with an ERV (Energy Recovery Ventilator) and is the cornerstone of our offerings to commercial and public buildings in Illinois. CO2 based heat pumps have the potential to drive the costs down even further on this exciting approach.

How Does a Heat Pump Work?

A heat pump is different than electric heat and operates on a very clever principle that allows it to move heat, rather than generate it directly. This makes it a much more efficient way to heat and cool your commercial building compared to traditional systems like furnaces, boilers and air conditioners. But how exactly does it achieve this?

The key component in a heat pump is refrigerant, a specially chosen liquid that can easily absorb and release heat. The refrigerant circulates through a closed loop system within the heat pump. By changing the pressure of the refrigerant, the heat pump can manipulate its ability to absorb and release heat.

Here’s where the magic happens. In heating mode, the heat pump absorbs heat from the outside air, even when it’s cold outside. Even though the air might feel chilly to us, it still contains some thermal energy. The refrigerant, in its low-pressure state, is able to efficiently capture this heat. Then, the refrigerant is compressed, which significantly increases its temperature.

Finally, the hot refrigerant transfers its heat to the interior of your building, warming you up. The cooled refrigerant then circulates back outside to pick up more heat, and the cycle continues. This process is essentially the reverse of what happens in your refrigerator, where heat is extracted from the inside to keep your food cold.

How is CO2 a Good Refrigerant?

Carbon dioxide (CO2) is emerging as a strong contender in the world of refrigerants, and for good reason. Compared to traditional refrigerants, CO2 boasts several properties that make it an environmentally friendly and efficient choice. Let’s delve into the reasons why CO2 stands out.

Firstly, CO2 is a champion for environmental sustainability. Unlike many conventional refrigerants, CO2 has a zero Ozone Depletion Potential (ODP) and an ultra-low Global Warming Potential (GWP) of 1. This means it doesn’t contribute to the depletion of the ozone layer or significantly enhance greenhouse gas effects. In a world increasingly focused on combating climate change, CO2 presents a much greener alternative. And unfortunately, the world has more CO2 than in the past centuries because of how much fossil fuels we have burned.

Beyond its environmental benefits, CO2 shines in terms of performance. It boasts excellent heat transfer properties. CO2 can absorb and release heat very effectively, leading to faster cooling and heating cycles in refrigeration systems. This translates to improved efficiency and lower energy consumption for your building. Additionally, CO2’s high density allows for smaller pipes and compressors to be used in refrigeration systems, making them more compact and potentially less expensive.

What are the Downsides of Using CO2 as Refrigerant in a Heat Pump System?

It’s important to acknowledge that CO2 does have some drawbacks. Due to its high operating pressures, CO2 systems require sturdier components compared to traditional refrigerants. This can translate to higher upfront costs for installation by welding steel vs brazing copper refrigerant lines. Additionally, CO2’s effectiveness can be reduced in very cold climates, as it can transition from a liquid to a gas state at higher temperatures than some other refrigerants.

However, some new companies like Tequs in Norway are combining the promise of hydronic systems (hot water) with CO2 Heat Pump systems. The CO2 refrigerant is contained within the outdoor heat pump system, and ultra hot or cold water is piped through the building to indoor fan coil units, or even into existing ductwork systems. This exciting system has a lot of potential, possibly lower costs for installation, and far lesser environmental impact over Freon. And, way less energy usage like all heat pump systems.

What About American CO2 Heat Pump Companies?

In fact, there are some exciting new American designed and manufactured CO2 heat pump systems. In July, Verde was able to tour the headquarters of Flow Environmental Systems in Minneapolis. Flow is a Minnesota-based engineering company specializing in environmentally friendly HVAC&R (Heating, Ventilation, Air Conditioning, and Refrigeration) technologies. Their primary focus is on developing and manufacturing innovative heat pumps that utilize carbon dioxide as a refrigerant.

Based in Hennepin County, Minnesota, which has very low winter temperatures, this company is on the cutting edge of industrial heat pumps. They have patented heat pump technology that uses carbon dioxide as a refrigerant to be more efficient, operate in wider temperature ranges, and be more environmentally friendly.

With decades of industrial refrigeration, this team is putting together a product that will solve a lot of industry problems including on tool to replace steam heat, large scale refrigeration systems, and total building cooling. We saw one of their “ANSWR”s in action.

Built to be modularly serviced and repair after lots of experience in the industry – these impressive pieces of equipment can really drive large amounts of water to a very high temperature – solving problems in the HVACR industry that VRF air sourced heat pumps cannot currently accomplish.

They can also combine their systems into three designs, which is clever. All of these systems deliver water up to 180 degrees, which is incredibly advanced.

First, you can design a simple Water-to-Water Heat Pump, which are used for hydronic distribution systems. These heat pumps feature true simultaneous heating and cooling so that they can provide multiple duties with one power feed. Typical applications include Chillers, Boilers, DHW, Central Plants, and Heat Recovery. The capacity range is about 300 MBH to 2000 MBH.

Next, you can design Split Air to Water Heat Pumps. These systems can also be matched or unmatched load heat recovery devices. Split systems are helpful for applications where it is beneficial to locate the heat pump and gas cooler in separate locations for either space or mechanical or electrical restraints. Typically, a heat pump would be in a mechanical room, and the gas cooler would be outside. These heat pumps feature true simultaneous heating and cooling so that they can provide multiple duties with one power feed. These can get to a slightly lower 1400 MBH maximum on a single system. These systems involve more piping between the inside and outside areas, with higher installation costs.

Finally, you can have Packaged Air to Water Heat Pumps, which are used for hydronic distribution systems. These systems can also be matched or unmatched load heat recovery devices. Advanced defrost design. Packaged systems make installation very easy and are typically installed outside. Units come 100% assembled and tested. Just install the unit and hook up water and power; there is no need for refrigerant piping onsite. These heat pumps feature true simultaneous heating and cooling so that they can provide multiple duties with one power feed and include advanced defrost.

How Can You Use Hydronic (Hot Water) in a Heat Pump System?

Heat pumps are renowned for their efficient heating and cooling capabilities. But what if you crave the even distribution of heat and the silent operation offered by hydronic systems, traditionally reliant on boilers? The good news is, you can have the best of both worlds! Here’s how heat pumps can seamlessly integrate with hydronic systems.

The magic lies in air-to-water heat pumps. Unlike traditional air-source heat pumps that directly blow heated or cooled air throughout your home, air-to-water models extract heat from outdoor air and transfer it to a circulating water loop. This heated water then becomes the workhorse, silently flowing through your existing hydronic system’s network of pipes and radiators.

The benefits of this synergy are numerous. Firstly, heat pumps excel at extracting heat from even moderately cold outside air, making them efficient in most climates. This warm water then feeds your existing hydronic system, which is a master at evenly distributing heat throughout your home. Radiant floor heating, for example, provides a comfortable warmth that rises gently from the ground, eliminating drafts and hot and cold spots.

Furthermore, this marriage of technologies leverages the strengths of each system. Heat pumps are known for their efficiency, especially compared to traditional electric resistance heating. By using this efficient heat source to power your hydronic system, you can significantly reduce your energy consumption and enjoy lower running costs. Additionally, hydronic systems are inherently quiet, as they rely on the silent circulation of water. This, combined with the quiet operation of modern heat pumps, creates a remarkably peaceful heating and cooling experience.

What Problem Do CO2 Heat Pumps Solve?

Converting a boiler system to a heat pump system is often a complex and costly endeavor. One of the primary challenges lies in the fundamental differences between the two systems. Boilers generate heat through combustion, whereas heat pumps extract heat from the environment. This requires significant modifications to the heating system’s infrastructure. Existing piping and radiators may not be suitable for the lower temperatures produced by heat pumps, requiring potential upgrades or replacements. So currently, it is very expensive and intrusive on building occupants to install current heat pump technology.

Furthermore, heat pumps operate most efficiently in milder climates. In colder regions, their performance can decline, necessitating additional equipment like backup heating systems. While this backup heat only serves the coldest dozen days of the year, it is far less efficient than heat pump systems.

Another hurdle is the upfront cost. Replacing a boiler with a heat pump is generally more expensive initially. While the long-term energy savings can offset this cost over time, the upfront investment can be prohibitive for building owners. Additionally, the installation process can be disruptive, requiring significant labor and time. Fortunately, we expect a lot of federal, state and local utility incentives to help offset this cost.

Lastly, the complexity of the conversion process often requires specialized expertise. While many HVAC technicians are familiar with heat pumps, converting a boiler system to a heat pump system demands a deeper understanding of both technologies. Finding a qualified installer can be challenging, and the cost of their services can add to the overall project expense.

The Benefits of CO2 Heat Pumps

The potential benefits of improved efficiency, even heat distribution, and quiet operation make the combination of heat pumps and hydronic systems a compelling choice for many Illinois buildings. And since 60% of our buildings are going to need to transition away from natural gas by 2050 – we need every trick in our toolbelt to get there. Using Hot and Cold water lines combined with heat pumps is a great strategy to get there. And this technology is only at the beginning – with big improvements to come in the next few years to bring down costs, improve efficiency and see more of these in action in Illinois.

Overall, CO2 presents a compelling option for the future of refrigeration. Its environmental benefits, exceptional heat transfer properties, and potential for efficiency gains make it a strong contender. While some challenges exist, ongoing advancements in technology are continuously improving CO2 systems, making them a viable and sustainable solution for a variety of commercial and residential applications.

Reach out to Verde for an energy efficiency assessment today for your commercial building in Illinois. Whether you consider a high efficiency replacement or a Very High Efficiency system replacement, we are h ere to help and advise.

 

Geothermal and air source heat pumps have a lot in common – in fact, they are essentially the same technology, just using a different way to expel and capture heat. One uses the air, and one uses the ground.

Air source heat pumps and ground source heat pumps are both types of heat pumps that utilize electrical energy to move heat around your commercial building, offering efficient heating and cooling. They function by extracting heat from a source and transferring it to your building. However, the key difference lies in where they extract this heat from.

Ground source heat pumps, also known as geothermal heat pumps, tap into the constant and moderate temperature of the earth. They achieve this by burying a network of pipes underground, either horizontally or vertically. These pipes circulate a fluid that absorbs heat from the ground and carries it back to the heat pump unit inside your home, where it’s processed and distributed as warm air.

Air source heat pumps, on the other hand, extract heat directly from the outside air. An outdoor unit draws in ambient air, even in cold weather, and concentrates the thermal energy it contains. This concentrated heat is then transferred inside your home to provide warmth.

A Very High Efficiency HVAC system has an air sourced heat pump with an ERV (Energy Recovery Ventilator) to save energy on the fresh air ventilation system. But you could certainly combine this same approach with geothermal and combine those with an ERV.

What is the cost Difference Between Air Source Heat Pumps and Geothermal?

The main advantage of air source heat pumps is their significantly lower upfront cost. Since there’s no need for extensive underground installations, the initial investment is much less compared to ground source heat pumps.

If you have lots of land, this may not be a huge difference. You do need to dig up the ground, and then lay vast loops of piping for the heat to be exchanged underground. If you don’t have lot’s of land, you can solve this by doing deeper. Going deeper, especially in scenario with lots of neighbors, is expensive.

However, it’s important to consider the trade-offs. While air source heat pumps are a budget-friendly option, their efficiency can be impacted by extreme outdoor temperatures. In very cold climates, the heat extraction process becomes more challenging, requiring the heat pump to work harder and potentially leading to higher electricity bills. In contrast, ground source heat pumps maintain consistent efficiency throughout the year because the ground temperature remains relatively stable.

Why Heat Pumps Reign Supreme in Efficiency over Natural Gas

While both natural gas furnaces and heat pumps provide warmth in your home, there’s a clear winner when it comes to efficiency: the heat pump. Let’s delve into four key reasons why heat pumps outperform natural gas systems.

Unlike natural gas furnaces that burn fuel to generate heat, heat pumps act like incredibly efficient movers. They capture heat energy readily available in the outside air, even during cooler temperatures. This captured heat is then concentrated and transferred to warm your home. Since they’re not creating heat from scratch, but rather relocating it, heat pumps achieve a much higher efficiency rating. This translates to significant energy savings on your utility bills.

Heat pumps boast a Coefficient of Performance (COP) rating, which indicates how much heat they deliver for every unit of electricity they consume. A typical heat pump can have a COP of 3, meaning it delivers three units of heat for every one unit of electricity used. In comparison, a high-efficiency natural gas furnace might reach an efficiency of around 90%, meaning it loses 10% of the energy it uses. This stark difference in efficiency showcases the clear advantage of heat pumps.

It’s true that extremely cold climates can affect heat pump performance. However, advancements in technology have equipped them to handle lower temperatures effectively. Additionally, in most regions, even with a slight dip in efficiency during very cold snaps, heat pumps still outperform natural gas furnaces throughout the year. So, even if your winters are harsh, a heat pump remains a more efficient and potentially cost-saving choice in the long run.

Which Saves More Energy in the Long Run, Geothermal or Air Source Heat Pump?

Over the long haul, a geothermal system will use less energy than an air sourced heat pump. However, it would be important to determine the additional cost of a geothermal system, to decide if it is better for your facility in the long run.

We performed energy efficiency services for a library that had Geothermal in Chicagoland, and they were very happy with the system. We have also installed air sourced heat pump systems for schools in Oak Park IL, and they also were very comfortable and saved over 60% compared to their past system. Both are great leaps forward in terms of energy efficiency, but geothermal is a bit better because of how moderate the ground stays in terms of temperature.

Are There Grants for Geothermal and Air Sourced Heat Pumps in Chicagoland?

Yes, there is a growing support for heat pumps, both geothermal and air source, for commercial work in Illinois.

Geothermal heat sourced tends to have more, including federal support from the Inflation Reduction Act. Locally, Comed is still studying some of the savings of projects we have completed – so rebates will be set on those.

Illinois has a goal of 60% of buildings electrified by 2050 – so geothermal and air source heat pumps will be prevalent in 2% more buildings each year until that time. So that means incentives at the state level are likely to come – and now is the right time to be thinking and planning for this important decarbonization transition. Reach out to Verde for an energy efficiency assessment today for your commercial building in Illinois.

 

Heat pumps are talked about a lot and they are highly efficient at creating heat and removing heat. In fact, many of our hopes for reducing a carbon footprint of a building relies on the promise of heat pumps.

A Very High Efficiency HVAC system is an ERV (Energy Recovery Ventilator) combined with a VRF (Variable Refrigerant Flow) Heat Pump system. Combining these two systems brings in plenty of fresh outside air, but allows you to design a smaller heat pump system since the energy is recovered in the outgoing air. In fact, this can drive the efficiency of a heat pump from a COP of 4 to a combined COP of 6. We will upback this information in this article.

How Do Heat Pumps Work in Commercial Buildings?

Heat pumps defy the laws of thermodynamics. They don’t actually create heat, but instead act like clever agents, stealing heat from one place and delivering it to another. In colder months, a heat pump extracts heat from the surprising source: the outside air. Even when the air feels chilly to us, it still contains thermal energy. The heat pump’s magic lies in its ability to capture this energy and concentrate it to warm your building.

The secret behind this heat transfer is a special substance called refrigerant. Refrigerant is a liquid that can easily absorb and release heat as it changes state. Inside the heat pump, the refrigerant circulates through a closed loop system. In one part of the loop, the refrigerant absorbs heat from the outside air, even in cold conditions. This causes the refrigerant to evaporate, turning from a liquid to a gas. We’ve been using refrigerants for years in refrigeration and air conditioning.

Once the refrigerant has absorbed heat and become a gas, it travels to another part of the loop where a compressor comes into play. This compressor is essentially a powerful pump. It squeezes the refrigerant gas, forcing its molecules closer together. As the pressure on the gas increases, something interesting happens: its temperature also rises significantly. This compressed, high-temperature refrigerant is now perfectly suited to deliver heat indoors.

The final stage of the heat pump’s cycle involves transferring the captured heat to your building. The hot refrigerant gas travels to an indoor heat exchanger. This heat exchanger acts like a bridge, allowing the heat from the refrigerant to flow into the air circulation system of your building. The warmed air is then distributed throughout your space, creating a comfortable and cozy environment. Meanwhile, the cooled refrigerant completes the loop, ready to pick up more heat from the outside air and start the cycle all over again.

What is the Coefficient of Performance of a Heat Pump?

Traditional heating systems, like furnaces or electric resistance heaters, convert one form of energy (electricity or fuel) directly into heat. While they get the job done, this process can be wasteful. Heat pumps, however, operate on a completely different principle. They boast an impressive efficiency rating measured by a value called the Coefficient of Performance (COP). Unlike traditional heaters with a COP of 1 (meaning they output exactly the same amount of energy they consume), heat pumps can achieve a COP of up to 4.

So, what exactly does a COP of 4 signify? Imagine this: for every 1 unit of electrical energy a heat pump consumes, it can deliver up to 4 units of heating output. That’s a remarkable feat! This efficiency stems from the heat pump’s ability to move existing heat, rather than generate it directly. By capturing heat from the outside environment and concentrating it for indoor use, heat pumps get a lot more mileage out of the energy they use.

It’s important to note that a COP of 4 is the upper limit for ideal conditions. In real-world scenarios, the COP of a heat pump will fluctuate depending on several factors. Colder outside temperatures can affect the ease of heat extraction, lowering the COP. Conversely, milder climates allow heat pumps to operate at peak efficiency, potentially reaching closer to that impressive COP of 4.

Despite some variation, the overall concept remains clear: heat pumps offer a significant advantage in terms of efficiency compared to traditional heating systems. With a COP reaching up to 4, they translate to lower energy bills and a reduced environmental footprint. This makes them a compelling choice for sustainable and cost-effective home heating.

Source: Energyeducation.ca

Are Heat Pumps Good for the Environment?

No matter how efficient a natural gas or propane heat system is, it always releases CO2. Most commercial rooftops have packaged rooftop units, and those are only 80% efficient in using the natural gas to create heat. 20% is wasted, but again – all of it releases climate changing gases.

In our local grid in Illinois, 53% of our energy comes from Nuclear Power. While it has it’s own concerns, it does not release CO2. There is also 20% wind powering our grid, along with increasing solar PV and some small amount of hydroelectric in our state. That all adds up to almost 80% of our electricity being clean in terms of global warming gasses – quite a feat for a midwestern state.

So heat pumps are incredibly good for the environment in general, and twice as good in a state like ours with plenty of clean energy. In fact, most of our energy usage peaks in the summer with heavy Air Conditioning, leaving the heating season with more capacity to add heat pumps. Heat pumps are better for the environment than traditional heating – by far.

Can a Heat Pump Exceed a COP of 4?

A heat pump cannot realistically exceed a COP of 4. The laws of thermodynamics, specifically the second law, dictate that no system can be 100% efficient in transferring thermal energy.

COP stands for Coefficient of Performance. It’s a ratio between the useful heating output (heat delivered to the building) and the electrical energy consumed by the heat pump. A COP of 4 means the heat pump delivers 4 units of heat for every 1 unit of electricity used.

Even the most ideal heat pump can’t overcome the limitations of physics. Moving heat from a colder source (outside air) to a warmer source (your building) requires work. This work consumes some of the electrical energy used by the pump.

Under perfect conditions, with minimal temperature differences between the outside and inside, a heat pump could theoretically reach a COP of around 6-7. However, these conditions are not achievable in real-world applications.

While exceeding 4 isn’t possible, some advanced heat pumps can achieve COPs close to 4 in ideal settings with mild climates. However, as the temperature difference between the outside and inside increases (colder outside), the COP will decrease.

Can a Heat Pump Plus Energy Recovery Ventilator System Exceed a COP of 4?

Yes, this combination can drive the efficiency of a heat pump system higher, but decreasing the amount of energy lost via the ventilation. Since Energy Recovery Ventilators reclaim up to 93% of energy, it means you can size down a heating or cooling system greatly.

Another way of saying COP is how much more efficient is something over the standard of electric or gas heating? Well, a COP of 6 would be 600% more efficient than the standard equipment – try that out at your next thanksgiving meal!

Do Heat Pumps Save Energy?

Yes, heat pump systems can significantly save energy compared to traditional heating systems like electric resistance heaters or furnaces. Here’s why:

Traditional heating systems directly convert electricity or fuel into heat. This process can be wasteful, as some energy is lost during conversion. Heat pumps, on the other hand, work by transferring existing heat from the outside air into your building. They essentially act like movers, not creators, of heat, making them inherently more efficient.

Heat pumps boast an impressive efficiency rating measured by COP. Unlike traditional heaters with a COP of 1, heat pumps can achieve a COP of up to 4. This means for every 1 unit of electrical energy a heat pump consumes, it can deliver up to 4 units of heating output.

The key to a heat pump’s efficiency lies in its ability to capture and concentrate heat that already exists in the outside environment, even in cold weather. This eliminates the energy wasted in generating heat directly, leading to significant energy savings.

Heat pumps operate most efficiently in moderate climates. Colder outside temperatures can make it harder for the heat pump to extract heat, lowering the COP during the coldest days. But those days are not as common as they used to be, making heat pumps even more impactful.

Overall, despite these factors, heat pumps offer a clear advantage in terms of energy savings compared to traditional heating systems. Their ability to move existing heat with a high COP translates to lower energy bills and a reduced environmental impact.

Conclusion on the Efficiency of Heat Pumps

We recently engaged with an independent firm to study the energy savings of a heat pump system, installed at the Oak Park Temple in Illinois. This ambitious project took almost 18 months from start to finish, and completely replaced their old boiler system, packaged RTUs, and window ACs. It also replaced some water “pump and dump” systems for cooling, which are now illegal because of the huge waste of water.

This independent verification showed a 60% reduction in energy usage after the heat pumps were installed with the combination of the ERVs. But more importantly, it brought fresh air into the building for the first time in decades, dramatically improving the safety for kids in school and improving the overall building health.

 

We recently had an experience where a customer decided to go with a traditional heating and cooling system upgrade over a Very High Efficiency HVAC upgrade. A Very High Efficiency HVAC system is an ERV (Energy Recovery Ventilator) combined with a VRF (Variable Refrigerant Flow) Heat pump system. Combining these two systems brings in plenty of fresh outside air, but allows you to design a smaller heat pump system since the energy is recovered in the outgoing air. In fact, these systems can save up to 80% on energy costs and have a huge benefit in reducing the carbon footprint of a building.  

I realized through this experience that we failed to educate the customer fully on the difference between electric heating systems vs VRF heat pump technologies. When the project was considered by the board, one of the board members was very critical of electric heating for buildings, due to a previous expensive experience in building operations. While both electric resistance heating use electricity as a  primary source of power, they are very different in energy usage, technology and cost to operate. 

What is Electric Resistance Heating? 

Electric resistance heating works on a simple principle: the conversion of electrical energy into heat through resistance. It’s like a glorified toaster element, albeit more sophisticated. Here’s the breakdown:

The Resistor: The core of electric resistance heating is a material with high electrical resistance, like nichrome, nichrome, or tungsten. When electricity flows through this material, it encounters opposition, causing tiny vibrations within the atoms. These vibrations translate into heat.

The Energy Conversion: The amount of heat generated depends on two factors: * Resistance: Higher resistance leads to more heat generation. Think of it like a narrower pipe – the water has to push harder, generating friction and heat. * Current: More current passing through the resistor creates more collisions and friction, leading to even more heat.

Transferring the Heat: Once the resistor gets hot, it needs to transfer the heat to its surroundings. Different appliances do this in different ways: * Space heaters: Fans blow air over the hot element, warming the air that circulates and heats the room. * Baseboard heaters: The hot element warms a metal plate, which radiates heat into the room. * Electric furnaces: Similar to space heaters, a blower pushes air over a series of hot coils, warming the air that gets distributed through ducts.

Environmental Applications of Electric Resistance Heating:

Beyond simple heating, electric resistance heating also has applications in environmental remediation. By passing current through contaminated soil, the heat generated can evaporate pollutants, allowing for easier extraction and treatment.

Key points to remember:

• Electric resistance heating is simple, reliable, and efficient (almost 100% of the electricity is converted to heat).
• It doesn’t require combustion, eliminating fumes and making it suitable for indoor use.
• However, it can be expensive due to the high cost of electricity compared to other heating sources like natural gas.

What is a Heat Pump?

Heat pumps are versatile and efficient systems that can provide both heating and cooling to your building, using the same basic principle as your refrigerator or air conditioner. While historically, they are not made for cold weather, the technology has improved and they now work up to 85% of capacity down to negative 10 degree Fahrenheit. Brrrrr. Here’s how they work:

The Magic of Refrigerant

At the heart of a heat pump lies a special liquid called refrigerant. This refrigerant can absorb and release heat as it changes between its liquid and gaseous states. It’s like a heat taxi, picking up warmth in one place and dropping it off somewhere else.

Think of as you boil water. It takes a lot of heat to do this, usually from a natural gas or wood fire. But, if you have a refrigerant change state because of pressure changes from liquid to gas – it still takes a lot of heat (or absorbs a lot of heat). Remember that old formula, PV = nRT?

Two Modes, One System

A heat pump can operate in two modes, driven by a reversing valve that directs the flow of the refrigerant:

• Heating Mode: In this mode, the heat pump acts like a reverse air conditioner.
  • The outdoor unit’s evaporator coil absorbs low-grade heat from the outside air, even when it’s extremely cold.
  • The compressed refrigerant carries this absorbed heat to the indoor unit’s condenser coil, where it releases the heat, warming the air that circulates in your home.
• Cooling Mode: This mode works like a traditional air conditioner.
  • The indoor unit’s evaporator coil absorbs heat from the warm air inside your home.
  • The compressed refrigerant carries this heat to the outdoor unit’s condenser coil, where it’s released into the outside air, cooling your home.
• Heat Recovery Mode: There can even be a super cool third mode, where the system can move heat from one space inside the building to another. It can do this with a small box that the gas and liquid can change state within the building, called a branch selector box.

Beyond Air: Different Heat Sources

While some heat pumps use outdoor air as their heat source, others can tap into other sources, like the ground or water:

• Ground-source heat pumps: These extract heat from the Earth’s constant underground temperature, making them highly efficient, especially in colder climates. This is geothermal heating and cooling – something more efficient than air-sourced heat pumps, but also more expensive and requires more land usage. You can go either very deep, or very long and wide in a property to get the proper surface area to heat and cool a building.
• Water-source heat pumps: These use water from lakes, rivers, or wells as their heat source. In Chicago, it is illegal to use water from Lake Michigan, although what a wonderful source of cooling that would be in the summer-time.

Benefits of Heat Pumps

• Energy Efficiency: Compared to traditional electric heating or gas furnaces, heat pumps can be significantly more efficient, translating to lower energy bills.
• Versatility: They provide both heating and cooling in one system, eliminating the need for separate units.
• Environmental Friendliness: Heat pumps don’t generate heat themselves, they transfer it, making them a more sustainable option for reducing your carbon footprint.

Things to Consider When Considering Heat Pumps

Heat pumps can have a higher upfront cost than traditional systems. While prices are dropping on the equipment, labor is critical to connect all of the refrigeration lines needed. This is typically done by brazing, which is done with a small torch that permanently connects the copper lines where the refrigeration lines run. This is important as refrigeration gases themselves are global warming gasses, so making sure they do not leak is critically important.

Heat pumps are also more electrical and refrigeration components that traditional HVAC equipment. For this reason, many contractors are unfamiliar with the process of installing them. As more and more contractors become confident, the prices will decrease. In fact, we really think of heat pumps to be more akin to walk in coolers and freezers, with a lot of electrical and communication lines running between them. It is important to have a good partner to set up the system correctly from the beginning.

Some air-source heat pumps may have reduced efficiency in extremely cold climates. It is important to select the correct version of the heat pump for your climate. Daikin, the original company to first release the VRF system in the 1980s, has several lines of commercial equipment. The Emerion, for example, has 85% heating at 0 degrees Farenheit. That is great, but at -10 degrees Farenheit, the system will not produce as much heat. This means you either need to accept that your building will be cold, have another supplemental system to provide heat, or put in way more BTUs of heating in your system than you need 99% of the year just for the extreme cold protection.

However, the Aurora system allows 85% heating down to -13 degrees Fahrenheit, a much more effective system for cold weather climates. This small difference in units from the same manufacturer can really impact both comfort, but also cost on the number of units needed for your system. While more and more engineers are getting comfortable with heat pumps, it is nice to work with someone experienced and confident in VRF heat pumps.

Overall, heat pumps are a smart choice for those looking for an energy-efficient and versatile heating and cooling solution. If you’re considering a heat pump, consult with a qualified HVAC professional or design engineering firm to assess your needs and find the best system for your building.

Source: Energyeducation.ca

Which One Costs More to Operate?

Electric resistance heat costs far more than heat pumps to operate.  While they are efficient in theory, they take heat burned from natural gas at a power plant far away and run it through power lines to get to your building.  Over time and distance, that energy is lost. A heat pump, however, just transfers heat from outside a building to the inside during the winter.  This is much more local, and therefore, less costly in almost every application.

Is a Heat Pump Good for the Environment?

No matter how efficient a natural gas or propane heat system is, it always releases CO2. Most commercial rooftops have packaged rooftop units, and those are only 80% efficient in using the natural gas to create heat. 20% is wasted, but again – all of it releases climate changing gases.

In our local grid in Illinois, 53% of our energy comes from Nuclear Power. While it has it’s own concerns, it does not release CO2. There is also 20% wind powering our grid, along with increasing solar PV and some small amount of hydroelectric in our state. That all adds up to almost 80% of our electricity being clean in terms of global warming gasses – quite a feat for a midwestern state. So heat pumps are incredibly good for the environment in general, and twice as good in a state like ours with plenty of clean energy. In fact, most of our energy usage peaks in the summer with heavy Air Conditioning, leaving the heating season with more capacity to add heat pumps.

What if I have solar PV on my building?

Solar PV is a great partner to heat pumps, far better than electric resistance.  For the same number of solar panels, you could put a lot more heat into a building as compared to electric resistance, at least three times as much in theory.  Or, if you already have heat pumps, you would need far less solar PV panels to provide enough energy to heat your building.

And, but adding the infrastructure now in terms of copper lines and communication systems, you will only get more heating bang for your buck as the systems increase in efficiency, both solar and heat pumps.

Conclusion

As we move toward new technologies to solve some of our greatest challenges, we will need to focus on education to get momentum. Heat pumps do work in cold weather – we have the data and the local experiences to prove that.  VRF heat pump systems are also far different from traditional electric heating sources in technology, and they are far less expensive to operate in terms of electricity costs to warm a building.  

VRF Heat pumps are electric driven, but they are not electric heating. They are using electricity to bring heat from outside a building to the inside (and vice versa in the summer).  If a customer has electric heating right now and converts to a VRF heat pump system, the cost to warm the building will drop significantly, up to 70% reduction.  And, if a customer has natural gas heating and converts to a VRF heat pump system, the heating costs will also reduce by about 30-40% in our experience. But the true winning is in reduction of global warming gasses, especially in a very clean state like Illinois.

Finally, and possibly most importantly, we have found that the Variable Flow Refrigeration aspect of heat pumps leads to a far more comfortable experience for the client vs traditional electric resistance heating, since it can give you a very granular temperature control of each room.  And to make a transition to decarbonized heating systems, comfort is the key.