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Decarbonizing buildings with geothermal energy heat pumps 

October 20, 2023/in From the Blog /by renew

RENEW Energy Partners specializes in funding energy-saving retrofits for your commercial, industrial, and institutional buildings. We install many different technologies to make your buildings more efficient and reduce your energy bill. One strategy for significant savings is upgrading your HVAC systems to use geothermal energy.

What is geothermal energy?

Geothermal energy is a form of renewable energy that takes advantage of the temperature difference between the air outside and deep underground. Underground temperatures are more stable than above ground. This effect is exaggerated the deeper you go, with underground temperature stabilizing at about 10 degrees Celsius (50 degrees Fahrenheit) 30 feet under the ground all year. Moving heat from the ground in the winter and to the ground in the summer can dramatically reduce the energy required to meet a building’s heating and cooling needs year-round.

Significant progress has been made in over the last decade in reducing electricity use in buildings and installing renewable sources of electricity such as on-site solar, but the same has not been true of building heating and cooling systems which typically center on oil or natural gas fired boilers. RENEW Energy Partners can fund installation of geothermal heat pumps as an energy-saving retrofit and as a part of new construction, and thereby reduce reliance on fossil fuels on site, reduce energy costs, and reduce a building’s carbon footprint.

What are geothermal energy heat pumps?

Just as an air-source heat pump moves heat through the air from the inside to the outside in summer and from the outside to the inside in winter, a ground-source heat pump uses the heat from the Earth instead of the air. Because the temperature underground is a constant 50F, fluctuating much less than air temperatures, geothermal heat pumps can more efficiently heat and cool buildings than their air-source counterparts.

In colder climates, it is common to incorporate an electric heat source to provide supplementary or backup capacity. Heat pumps can be more environmentally friendly since they do not burn fossil fuels like oil or gas furnaces. Because these systems utilize that constant 50F heat from the earth they may also consume less energy than boilers or furnaces to provide the same heat, lowering a building’s energy cost.

Water Source Geothermal Heat Pumps (WSHP)

While ground-sourced heat pumps are what most people think of when they think of geothermal, water-source geothermal heat pumps are equally useful. They use bodies of water as a heat sink or source. This is often groundwater beneath the earth’s crust but can also be from a nearby body of water.

Types of Geothermal Heat Pump Systems:

Ground Loop Systems

Geothermal heating and cooling systems can be categorized into two types: open loop and closed loop. Open loop systems interact directly with the water source, whereas closed loop systems interface with the water source via a loop of coils of plastic tubing connecting in and out of the building. While closed loop systems tend to be the most common, the system choice depends on factors such as climate, soil conditions, available land, and installation costs. All buildings can utilize these systems, but they are especially cost effective when performing large retrofits for commercial, institutional, and industrial buildings.

Open Loop Systems

Open loop systems in geothermal heat pump (GHP) systems use well or surface body water as the heat exchange fluid. The water circulates directly through the GHP system and then returns to the ground through a well, recharge well, or surface discharge.

Closed Loop Systems

Closed-loop geothermal heat pump systems, commonly used in geothermal heating and cooling, circulate an antifreeze solution through an internal plastic tubing circuit buried in the ground or submerged in water. The heat exchanger plays a vital role in transferring heat between the refrigerant in the heat pump and the antifreeze solution. Another type of closed-loop system called direct exchange, uses copper tubing buried in the ground without a heat exchanger. The three types of closed loop systems are horizontal, vertical, and pond/lake.

Horizontal Systems

The horizontal loop system is the most cost-effective installation for geothermal systems, particularly in residential settings. The most common layouts involve using two pipes buried at different depths or side-by-side in a trench. This requires a shallower dig but requires more land relative to its capacity.

Vertical Systems

Large commercial buildings and schools often have land as a constraint. Vertical systems help bypass these limitations by using shallow soil while minimizing disruption to existing landscaping. Dig costs can be significantly higher than a horizontal system.

Pond/Lake Systems

These systems could be the most affordable option if a system has access to a body of water. A supply line pipe is run underground from the building to the water and coiled into circles at least eight feet under the surface to prevent freezing. The coils should only be placed in a water source that meets minimum volume, depth, and quality requirements.

Hybrid Systems

Hybrid systems combine different geothermal resources or a geothermal resource with outdoor air (such as a cooling tower). They are a viable technological option for meeting cooling needs greater than heating needs.

How can the use of Geothermal Heat Pumps reduce carbon emissions?

Geothermal heat pumps (GHPs) can significantly reduce carbon emissions by utilizing the Earth’s natural heat. Specifically:

High Efficiency

Efficiency is a major strength of geothermal systems. These systems transfer heat between the building and the ground, which requires less energy than traditional HVAC systems. This increased efficiency leads to reduced energy consumption and lower greenhouse gas emissions. For more information on HVAC upgrades using heat pumps, see our blog post on the future of HVAC retrofits.

Renewable Energy Source

Geothermal heat pumps provide a renewable energy source for heating and cooling systems. Unlike fossil fuel-based systems, these pumps extract heat from the Earth’s core, continuously generating heat through natural processes. This ensures a consistent and sustainable energy supply for the heat pump.

Lower Electricity Demand

Since geothermal heat pumps require less energy to operate than conventional HVAC systems, they can help reduce the overall electricity demand of a building. Lower electricity consumption means fewer emissions from power plants, especially if the electricity is generated from fossil fuels.

No Combustion Emissions

Geothermal heat pumps do not burn any fuel to produce heat. Instead, they use electricity to facilitate heat transfer. This absence of combustion emissions eliminates the release of carbon dioxide (CO2) and other harmful pollutants associated with traditional heating systems, such as gas or oil furnaces.

Heat Recovery

Geothermal exchange systems can recover waste heat from cooling processes and utilize it for other purposes, such as water heating. This improves their energy efficiency and reduces their reliance on additional energy sources.

Long Lifespan

Geothermal heat pumps generally have a longer lifespan than traditional HVAC systems. Their underground components can last for decades in areas that aren’t tectonically active, reducing the need for frequent replacements and associated manufacturing emissions.

Grid Independence

In some cases, geothermal heat pumps can be used in off-grid or remote locations where connecting to a centralized power grid might be difficult or environmentally damaging. They can mitigate the environmental impact of extending power infrastructure to these areas by operating independently.

What are the financial benefits of using geothermal energy for building owners?

Reduced Energy Costs

Geothermal heat pumps are energy-efficient and can greatly reduce the energy used for heating and cooling. Building owners implementing this energy retrofit can expect to see savings in energy costs, with noticeable results within a few years. The exact amount of savings will vary depending on factors such as the size and location of the building, as well as energy prices. However, it is common for building owners to experience significant reductions in utility bills.

Enhanced Property Value

Retrofitting commercial buildings to implement geothermal energy heat pumps may increase property value and market appeal. Energy-efficient and sustainable features can attract potential buyers or tenants, creating a competitive advantage in the real estate market.

Access to Incentives and Tax Benefits

Many governments and local authorities offer incentives and tax benefits to encourage the adoption of renewable energy for building decarbonization, including geothermal. Building owners may be eligible for grants, tax credits, or other financial incentives to offset the initial installation costs and improve the financial viability of the geothermal energy project. For instance, the Department of Energy has announced $13 Million to support geothermal heating and cooling in communities.

Positive Public Image

Renewable energy technologies like geothermal can enhance a building owner’s reputation and brand image. Demonstrating a commitment to sustainability and environmentally responsible practices can resonate positively with customers, stakeholders, and the broader community.

No matter how you decide to implement energy efficiency measures in your building, these kinds of projects require funding. To fund an energy efficiency project for your building(s), RENEW Energy Partners offers an energy service agreement (ESA). The Energy Service Agreement:

It may be treated as an off-balance sheet transaction. In that case, you do not own or carry the asset on your balance sheet (consult your tax advisor to evaluate your options).
RENEW provides preventive and corrective maintenance in the service agreement.
Your payment to RENEW will be based on the energy savings confirmed once the system is operational.

The RENEW Energy Service Agreement allows businesses to focus on what they do best while ensuring that their facilities are performing at their peak with brand-new and high-efficiency equipment. In this current climate of cost control and resource allocation, the energy service agreement is the perfect solution to help businesses meet sustainability goals and keep facilities in top condition. Reach out to RENEW and talk to us about financing your energy-saving retrofits today.

Sources: DOE

Exposed beams showing building insulation.

Energy Saving Retrofits: Building Envelope and Insulation

April 13, 2023/in From the Blog /by renew

RENEW Energy Partners specializes in funding energy saving retrofits for your commercial, industrial, and institutional buildings. There are many different technologies we can install to make your buildings more efficient and reduce your energy bill. One strategy for significant savings is to upgrade your building envelope and insulation to prevent energy from escaping and being wasted.

Building Envelopment and Insulation

Decarbonizing retrofits typically involve multiple aspects of a building’s systems, such as HVAC, lighting, and water usage. However, the building’s envelope and insulation are often the first place to start, as it can have a significant impact on a building’s energy use and GHG emissions. Upgrading HVAC and other mechanical upgrades are certainly important, but if you have a drafty building, even the most efficient heating and cooling systems will not be effective.

Insulation:

Insulation has to do with preventing heat flow through building perimeters. A building envelope keeps conditioned air inside the building. Together, they help keep buildings cool in warmer months and warm in cooler months.

Additionally, piping that carries hot water, steam, or chilled water to heating and cooling appliances needs to be insulated, and over time that insulation can break down and need replacement. Uninsulated hot water or steam pipes will lose heat constantly, leading to poor efficiency. Uninsulated chilled water piping has the same problem but can also cause condensation and lead to property damage.

When considering insulation options for decarbonizing retrofits, it’s important to consider the R-value, or thermal resistance, of the material. The higher the R-value, or the more heat resistant the insulation material, the better the insulation will perform.

Insulation plays a major role in the energy efficiency of a building. It can help keep the indoor temperature stable, reducing the need for heating and cooling systems. When selecting insulation materials for a retrofit project, there are several factors to consider, including budget, effectiveness, and environmental impact. Some common insulation materials include fiberglass, cellulose, and spray foam, but not all insulation materials are created equal.

Spray foam for example, is not always the best product. Its main advantage is that industrial applications are fast to apply in new build construction, so it’s generally cheaper. A more common retrofit technique is a siding replacement project, foam board (polystyrene) is added to the outside surface of a building, followed by a layer of “house wrap” vapor barrier, then new siding. Generally, you remove the existing siding first, but that depends on the existing construction method.

Building Envelopment:

The building envelope itself is made up of the walls, roof, windows, doors, and other exterior components of a building. It serves as a barrier between the interior and exterior of the building, protecting the occupants from the elements and providing thermal insulation. When a building is properly insulated and sealed, it can significantly reduce energy consumption and GHG emissions.

In addition to insulation, other aspects of the building envelope that can contribute to decarbonizing retrofits include windows and doors, roofing, and air sealing. Upgrading to high-performance windows and doors can also reduce heat transfer, while reflective roofing can minimize the amount of heat absorbed by a building. Proper air sealing can also help to prevent drafts and minimize energy loss.

Lastly, there are building management technologies on the market that focus on monitoring building envelope. Once installed, any air leaks can be detected easily and in real time, strengthening the building envelope and reducing maintenance costs.

Conclusion

Building Envelope and Insulation are often referred to in the energy industry as a building’s “lungs.” If there are holes in the lungs, then any air that is pumped into them has the possibility of leaking out. Any energy saving retrofits applied to HVAC systems will have minimal effect if a building is not well enveloped and insulated.

Updating a building’s envelope and insulation can help customers keep their buildings airtight, keeping the energy they produce within their walls for as long as possible. This helps maintain consistent internal environments and avoids excess energy output to continuously heat and cool indoor spaces.

No matter how you decide to increase your energy efficiency and decrease your carbon footprint, these kinds of projects require funding. In order to fund an energy efficiency project for your building(s), RENEW Energy Partners offers an energy service agreement (ESA). The Energy Service Agreement:

May be treated as an off-balance sheet transaction. In that case, you do not own the asset or carry it on your balance sheet (consult your tax advisor).

RENEW provides preventive and corrective maintenance in the service agreement.

Your payment to RENEW will be based on the energy savings confirmed once the system is operational.

The RENEW Energy Service Agreement allows businesses to focus on what they do best, while ensuring that their facilities are performing at their peak with brand new, and high-efficiency equipment. In this current climate of cost control and resource allocation, the energy service agreement is the perfect solution to help businesses meet sustainability goals and keep facilities in top condition. Reach out to RENEW and talk to us about financing your energy saving retrofits today.

HVAC Energy Efficiency Retrofits: The Basics

January 13, 2023/1 Comment/in From the Blog /by renew

RENEW Energy partners specializes in helping fund your energy saving retrofits for your commercial, industrial, and institutional buildings. There are many different technologies we can install to make your buildings more efficient and reduce your energy bill. One place to deliver significant savings is by heating and cooling your building more efficiently, with energy efficiency retrofits to your Heating, Ventilation, and Air Conditioning “HVAC.”

Last month we discussed the history of HVAC, a story where Willis Carrier’s practical solution to too much humidity in a publishing factory led to the first mass-produced Cooling and Ventilation System. Today, HVAC systems continue to get more efficient, regulating climates throughout modern buildings.

HVAC Retrofits

For energy efficiency retrofits, the first places you need to look are the upgrades that will save you the most money. You should aim for an HVAC system that is at least 80% efficient. If your HVAC is not as efficient, updating your system will reduce your energy bills. When updating your HVAC, you need to think about the following:

Basic Energy Efficiency Retrofits

- Economizers:
  - An economizer is a part of the outdoor system, most often mounted on the roof, of an HVAC system for commercial buildings. The economizer evaluates outside air temperature and even humidity levels. When the exterior air levels are appropriate, it uses the outside air to cool your building. HVAC economizers use logic controllers and sensors to get an accurate read on outside air quality. As the economizer detects the right level of outside air to bring in, it utilizes internal dampers to control the amount of air that gets pulled in, recirculated and exhausted from your building. It saves on energy, helps your A/C last longer, and improves air quality.
- Compressor/Condenser
  - The compressor reduces the volume of gas to add pressure to it. The compressor uses more power than any other component of an air conditioner, cutting down on how much power it uses helps immensely with increasing energy efficiency. Upgraded compressors provide the ability to operate at a lower capacity with controls that include Variable Frequency Drives.
  - An HVAC condenser takes the pressurized gas and turns it into liquid vapor.
  - Condensers and compressors should be upgraded at the same time to create the most efficient system possible.
- Condensate Recovery
  - In a typical commercial air conditioning system, warm, humid air from the building is run over a cold air handler that cools the air. When this is done, condensate water is created and recovered for reuse. A drip pan collects this relatively clean water, and it is discharged to a sewer.
  - With condensate recovery, that water is diverted to the cooling system, helping the system run more efficiently.
- Duct Insulation/Duct Sealing
  - To prevent air leaks, duct sealing is necessary along the entire length of the ductwork system. Air leaks in your ductwork system can account for a significant loss of energy and money, especially larger systems in commercial buildings. The most insulated method of construction continues to be pioneered by the Passive House International construction standard.
- Duct Size Optimization
  - Oversized Ducts: Larger than normal ducts are certainly capable of handling more airflow. But your HVAC system may not be equipped to pump that much air. In fact, your system needs a specific air pressure in the ductwork to properly distribute air. Oversized ducts could cause your HVAC system to work too hard and limit the amount of conditioned air that reaches your home. Forcing your system to work harder than it should leaves it prone to breakdowns and increases your energy usage.
  - Undersized Ducts: If your ducts are too small to accommodate the air flowing through them, the pressure increases and backs up in the system. This causes resistance for the blower fan, reducing your HVAC system’s efficiency and longevity. Over time, this can lead to significant stress on the components and can inevitably lead to a breakdown.
  - Duct Sizing Method: The Manual D Sizing Method is the industry standard that was developed by the Air Conditioning Contractors of America. This method involves evaluating the individual rooms in your home to determine optimal airflow, control excessive noise, seal ductwork, provide insulation, and retrofit the design as needed. This all works to correct pressure imbalances and ensure your system runs as efficiently as possible to supply each room of your home with adequate, conditioned airflow.
- Variable Air Volume (VAV)
  - Variable air volume (VAV) systems enable energy-efficient HVAC system distribution by optimizing the amount and temperature of distributed air. Appropriate operations and maintenance (O&M) of VAV systems is necessary to optimize system performance and achieve high efficiency.

- Heating and Cooling Recovery
  - This is the process of recovering excess thermal energy that would otherwise be emitted, in order to use it as energy and reduce your overall consumption.
  - Thermal energy can be recovered from water, air, or a ground source.
  - This can also fall under the umbrella of CHP (Combined Heat and Power), which could further reduce energy usage.

Chiller Upgrades.

For energy efficiency retrofits, it is important to specifically think about how your building is cooled. Freezer storage alone makes up about one percent of global emissions. Here are a few things to think about:

- - Chillers can be regulated by air or water. Air chillers are less expensive but use more energy.
  - Water chillers must be efficient and up to date to conserve and reuse water, but when maintained, are much more energy efficient.
- Chiller Controls
  - The most efficient ones we can install include Variable Frequency Drives (VFDs) that regulate the amount of energy needed throughout the day depending on internal and external temperatures.

- Modular Chillers
  - Modular chillers are ideal because each module can operate independently from each other. If one module fails, the other can continue to run. This is ideal for efficiency and maintenance.

- Heat Recovery Chillers
  - If heating and cooling are needed at once, heat recovery chillers can allow for the heat they emit to be redirected to other energy sources. These chillers don’t always get hot enough for cold climates but are ideal for mixed use spaces.

Conclusion

To summarize, when contemplating energy efficiency retrofits, updating your HVAC systems is a crucial way to decarbonize and save money. Additional savings can be made by implementing water saving retrofits. The most ideal systems interact with each other and redirect excess energy for further use. An energy management system and variable frequency drives can help you control and monitor your HVAC effectively so that it does not have to run at full capacity 24 hours a day. Stay up to date about HVAC energy efficiency retrofits by reading our most recent article on the future of HVAC retrofits. Finally, keep your buildings and pipes well-insulated to prevent energy leakage.

No matter how you decide to increase your energy efficiency and decrease your carbon footprint, these kinds of project require funding. In order to fund an energy efficiency project for your building(s), RENEW Energy Partners offers an energy service agreement (ESA). The Energy Service Agreement:

Is an off-balance sheet transaction. You do not own the asset or carry it on your balance sheet.

RENEW provides preventive and corrective maintenance in the service agreement.

Your payment to RENEW will be based on the energy savings confirmed once the system is operational.

Unlike a lease or a loan, which are on balance sheet, do not include maintenance, and may or may not deliver energy savings, the service agreement provides all of the above and then some:

Executing a service agreement is fast – once the project is scoped by an energy professional (and we can recommend one), you execute a simple service agreement contract and RENEW will fund the project.

Executing a service agreement frees up your capital budget for your other priorities, allowing you to focus on growing your core business.

Executing a service agreement now means your net cash flows are higher than waiting and doing it yourself in a year.

And finally – executing a service agreement means flexibility. Perhaps you buy another building or look at additional efficiency measures–with a one-page addendum to your existing ESA you can have those new lights, HVAC, and controls at your new building, and you simultaneously reduce your operating expense!

The RENEW Energy Service Agreement allows businesses to focus on what they do best, while ensuring that their facilities are performing at their peak with brand new, and high-efficiency equipment. In this current climate of cost control and resource allocation, the energy service agreement is the perfect solution to help businesses meet sustainability goals and keep facilities in top condition. Reach out to RENEW and talk to us about financing your energy saving retrofits today.

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Posts

What is geothermal energy?

What are geothermal energy heat pumps?

Types of Geothermal Heat Pump Systems:

How can the use of Geothermal Heat Pumps reduce carbon emissions?

What are the financial benefits of using geothermal energy for building owners?

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