Can Ground Source Heat Pump Systems Be Considered Renewable?

by Matt Napolitan on February 22, 2012

What is a ground source heat pump (GSHP)? A heat pump is an air conditioner that can cool in the summer and heat in the winter. The ground source part means that the heat removed from the building in the summer and the heat added to the building in the winter goes to and comes from the ground.

Illustration of a horizontal closed loop system shows the tubing leaving the house and entering the ground, then branching into three rows in the ground, with each row consisting of six overlapping vertical loops of tubing. At the end of the rows, the tubes are routed back to the start of the rows and combined into one tube that runs back to the house. Illustration of an open loop system shows a tube carrying water out of the house, into the ground, and over to a well, where it discharges into the groundwater. A separate tube in a well some distance away draws water from the well and returns it to the house.

(Images: EnergySavers.gov)

What’s a renewable resource? Merriam Webster defines it as a resource “capable of being replaced by natural ecological cycles or sound management practices.” Sounds accurate to me!

So why the question?

Governments and utilities often provide financial incentives for equipment or system approaches that are more efficient than code minimum requirements. Those incentives are usually based on the efficiency difference (or energy use difference) between the efficient case and the code minimum case. For example, code might require a boiler that’s 84% efficient. If you install a 94% efficient boiler, you may get a rebate based on the 10% efficiency difference. In the case of renewables, like solar photovoltaics (PVs), the incentives are based solely on system cost since there is no “baseline” to compare to and those incentives are often much higher as a percentage of cost than an “efficiency upgrade” incentive.

Recently, I’ve been party to lot of conversation around this topic with many folks coming down on the side of GSHP systems being renewables. I don’t believe that they are.

Why Aren’t GSHPs renewables?

GSHP systems, because they use a compressor just like an air conditioner does, require an electrical input to function.  Very well designed systems will require one unit of energy input to move between three and five units of energy between the building and the ground. That’s an input of between 20% and 33% of the total energy transferred. If you want to go further, figure in the inefficiencies of generation and transmission and that percentage goes way up.

Where does that electrical energy come from? The US Energy Information Administration (EIA) notes that in 2010 89% of the electricity on the US grid came from fossil fuels, coal or nuclear power – none of which are renewable resources, and all of which have a significant environmental impact when extracted, used, and disposed of. The EIA predicts that number will be 84% in 2035; not much different 25 years later. So on average, currently 89% of the electrical power required to operate a GSHP system in the US is from non-renewable sources. Of course, your specific locale or building may have a different energy source profile which certainly warrants consideration. For example, I live in Burlington, Vermont. We’ve got a wood-chip power plant that has a maximum capacity large enough to power nearly the entire city according to the Burlington Electric Department. Realistically, it does not always operate at maximum capacity nor does it always burn wood chips, but assuming it provides just half the city’s needs on average means Burlington’s renewable power profile is significantly different than the nationwide average. Or, you may simply cover your entire building with PVs which will change that source profile as well.

Why THIS MATTERS

GSHP systems, when designed correctly, are typically more efficient that other, traditional systems because of the ground coupling.  Ground temperatures are relatively constant throughout the year and in cooling season are lower that the ambient air temperature and in heating season, higher. Rejecting heat to a cool medium and extracting it from a “warm” one makes for a more efficient refrigeration cycle. They’re also usually more expensive than traditional systems due to the ground coupling which typically entails drilling wells that can be 400 to 500 feet deep each (for certain types of systems), or other similar means of ground coupling – all of which require long lengths of pipe and site work that are both in excess of what a traditional system would require. But because they’re more efficient, utilities and governments will provide incentives to owners to help offset the added cost.

It’s true that GSHP systems are potentially more efficient, and they deserve to be incentivized, just like the example above of the more efficient boiler. But truly renewable energy sources – wind, solar, geothermal, hydro, biomass – should be incentivized at higher relative rates than more efficient systems that do not use renewables. A higher incentive for renewable energy sources will serve to further encourage their implementation.

Related

NREL on GSHP
Department of Energy on GSHPs

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Sustainability and Corporate Culture Change

by Eveline Killian on February 15, 2012

Sustainability – defined here as the responsible management of natural resources to create a more robust, independent and environmentally conscious organization – is a pursuit being explored by more and more companies. The challenge for many corporate leaders and managers is how to initiate change in their company’s culture. How do you create such a sea change authentically: something that won’t sound like a gimmick or start with a bang and fizzle out within a brief period of time? Over the years I have seen a pattern to the steps taken by clients who have been successful in creating a corporate culture of sustainability.

Step One: Obtain Managerial Backing

This step is critical – if you can’t sell it to upper management, there’s no use in proceeding. It will end up being undermined and employees will quickly realize it’s not genuine. If the leadership makes it a directive for the company, you will be able to embed sustainability in your corporate mission statement, create a plan and set goals. There are consultants that can help with this, but if you’re a small firm, this can be a manageable task of some research and a few brainstorming sessions with other interested people.

The game-changer's compass

Step Two: Announce Your Vision to the World

This should happen through every medium at your disposal — through your company website (internal and external), e-newsletter, and professional blog. You want to get people talking – whether they are cynics or enthusiasts – and make the new vision synonymous with your company.

Step Three: Delegate Responsibility and Empower the People

The smallest step you can take with the largest, most enduring impact is to make the new priority of corporate sustainability part of an interested person’s job description. I worked with a small food manufacturer that advertised for a part-time “Environmental Coordinator” from within their workforce. A young, enthusiastic, albeit inexperienced person in the packing department was interested and it became a 20% position. Within a short time he had coordinated with a nearby paint company to take the empty 5-gallon containers the food manufacturer had been bringing to a recycler 30 miles away.

As a food manufacturer, they were not allowed to reuse the cleaned containers, and the paint company was buying brand new containers. This joint venture saved the food company the cost of recycling and the 60 mile round trip every week, the paint company got clean containers at a much lower cost, and the environmental cost of producing and disposing of the containers was averted.

It is important for the “Environmental Coordinator” to be empowered to identify opportunities within their department and bring it to a manager that has the authority to prioritize and enact the chosen ideas. It is also important for every person in the company to feel empowered to bring their ideas to these coordinators. This can be done in many ways – anonymous suggestion boxes, an internal website suggestion tab, or a whiteboard in the coordinator’s office – depending on the current culture of the company. It is also advantageous if an Environmental Coordinator can trade ideas and brainstorm with other coordinators on a regular basis. If there are multiple coordinators within one organization, the coordinators from each department could meet regularly to brainstorm, learn from each other and synergize their efforts (reducing costs, gaining support). One company I worked with started a multi-organizational environmental group. The Environmental Coordinators from six non-competing, like-minded companies met on a quarterly basis to trade ideas on issues such as recycling, environmentally friendly suppliers and efficient manufacturing ideas. (Vermont Businesses for Social Responsibility coordinates several such groups.)

Recurring Step: Keep People Informed

Announce your success stories, your current projects, ideas you’ve heard about, and relevant stories from other companies. These stories will reinforce the company’s commitment and celebrate your people. And these days many of these ideas are easy to track and quantify. For example, our company provides bus passes to all employees for free to encourage the use of mass transit for commuting. We can track the emissions savings by how many times an employee requests a new pass and how many miles of driving to work in a single-occupied vehicle this saves them. Our local school started a campaign to reduce the amount of printed material they created and found they don’t require recycling pick up as often – savings that are shown on their monthly overhead costs. Quantifying these savings is important in order to reinforce the significance of the new culture shift towards sustainability, empowering everyone from the CFO to the packer on the production line.

Be the change you want to see in the world

Word of mouth and cultural image are immensely powerful. People listen, judge and act in accordance with what they hear and see happening around them. Tell stories about your ideas and then share what you accomplished. These stories will paint a picture of what your company stands for and this picture will help to create the cultural shift you want to see.

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