Making HVACR Work off the Grid
Places to find advancements in such nongrid options are the various energy and environmental fairs that are occurring more and more in many parts of the country. One such event this summer was the 10th Illinois Renewable Energy and Sustainability Lifestyle Fair held in Oregon, Ill., about 100 miles west of Chicago. Educators, HVAC contractors, trade associations, manufacturers, and environmentalists were among those in attendance. The NEWS talked with a number of them specifically regarding the potential of HVACR equipment getting enough power from sources other than power grids or backup generators.
“There is a natural fit on the heating side,” said Andy Erbach, associate professor for the energy management program at Elgin (Ill.) Community College, which had a large mobile exhibit trailer on site. “Radiant panels and hydronics can be tied to solar thermal systems.”
He then noted, “Regarding the viability of sustainable a/c systems, while conventional split systems and air-to-air heat pumps are becoming more and more efficient, and SEER ratings are rising, I believe that the most energy-efficient methods of cooling a home are some of the oldest, such as shading, ventilation, proper window location, and proper building envelope design. These passive cooling systems have been used for centuries and are still effective today.
“In the area of mechanically driven, energy-consuming equipment, some of the most practical and efficient residential air conditioning systems today are those that are earth-sourced. Earth tubes and geothermal heat pumps are both examples of available technology that are used in this area to cool residences.”
Regarding residential refrigeration, Erbach mentioned photovoltaic for 12- to 24-V refrigerators.
The Commercial Sector
On the commercial side, he said, “That area is just as fertile for our (HVACR) industry” and involves use of solar heat and hot water. “In light industry, waste heat is being used.”
Whatever combination of equipment and power sources are being tried, he said, “The selection of appropriate technology depends on the individual situation; and requires that some fundamental questions be asked:
• Where is the energy going?
• Have you done a comprehensive energy audit?
• Where are the most cost-efficient improvements in the structure to be made?
• Are you building a new structure, or improving the environmental impact of an existing one?
• Do you expect to be grid tied or off the grid?
• Where in the world are you located?
• What are your expectations of an a/c system?
• Who owns the building?
• What do the local codes and laws permit?
Or as he cautioned, “Don’t just bolt some [perceived energy saving piece of equipment] to the side of
Dr. Robert Vogl, a board member of the Illinois Renewable Energy Association and one of the founders of the energy fair, pointed to geothermal technologies as helping HVAC “take some of its electrical power requirements off the grid. Whatever electrical service you can get that way is renewable energy.” He also encouraged attention given to PV which uses solar panels to convert sunlight into electricity. The PV modules, mechanical and electrical connections and mountings regulate and/or modify the electrical output. “Most PV systems are grid-connected and are worthy to look at,” he said.
He encouraged “matching output with the demand of equipment.”
Mark Burger, president of the Illinois Solar Energy Association, said, “HVAC contractors should be the most adaptable to selling a solar-engineered system because solar is a natural extension of heating and cooling equipment. Right now you have solar specialists and electrical contractors selling PV. But they are not set up to sell capital equipment like HVAC contractors are.”
He said, “Solar heating is moving into the American mainstream.” He did encourage HVAC contractors to look at third-party financing options and incentives as part of the equation. In noting some of upfront costs associated with alternative energy options, he said, “Selling cost is not the right thing to do. You have to look at proper financing packages.”
Chris Manny of Sustainable Strategies noted that one of his company’s strategies is “putting a wind turbine behind the meter to generate power for your agricultural, commercial, educational, or municipal use.”
He called that “the next phase of the business life cycle in the wind energy business.” Among HVAC aspects, he said, was with baseboard heating. He, too, was a strong advocate of PV which was discussed often throughout the two-day event.
Ellie Jackson of the Midwest Renewable Energy Association said contractors need to consider “how much power does a single solar panel offset for a condensing unit,” as part of her argument for contractors to look at all implications regarding alternative energy sources. At the same time, she noted instances of a small PV system running a refrigerator off the grid and a warehouse relying on collection panels and airflow configurations to keep the building off the grid in the heating season.
Contractors at the Show
There were two HVAC contractors exhibiting, and one of them, Synergy Heating and Cooling of Rockford, Ill., gave a seminar session to advocate geothermal.
Ryan Yelles of Synergy said, “Heat pumps are the right thing to do for our planet and our future.” He was especially strong in support of geothermal “to reduce dependency on nonrenewable resources such as natural gas and propane. It uses electricity, but it uses it efficiently.”
He also picked up on a recurring theme of the expo, that is, to make sure of the energy efficiency of the building to use geothermal. “First, money should go to making sure of the insulation of your home,” he said. “Make sure you are superefficient before you put your geothermal in.”
Can geothermal be augmented with solar? “Absolutely,” he said. But in such instances he did warn that “the challenge of getting off the grid means that the more backup generation, the more costly it will be.”
But it is worth it, he said. “Heat pump technology allows us to make better use of the nonrenewable resources we are currently using, while also opening the door to a completely renewable future.”
Sidebar: And the Industry Says…
As much as advocates of alternative energy sources say such sources will work with air conditioning and even refrigeration, there are those who are reluctant to do so just yet. One example is in the supermarket sector, which has a full gamut of HVACR technology — especially refrigeration.
“The implementation and use of renewable energy among food retailers is low,” said Anne-Marie Roerink, principal of 210 Analytics LLC, during a presentation in September at the Food Marketing Institute (FMI) Energy and Store Development Conference. The feedback was based on a survey of FMI store owner members.
She noted that 6.5 percent have installed solar panels, and 3.2 percent purchased green energy credits, but that no one of those surveyed had invested in wind energy. Regarding the latter, she quoted one responder as saying, “We tried wind energy, but found it is not yet economical to use.”
In the broader category of green energy, she did note that “54.9 percent said it was an added expense but the right path for the future, 29 percent saw it as a cost-savings tool and the right thing to do, 9.7 percent consider it a cost-savings tool, and 6.5 percent saw green energy as an added, unnecessary expense in this economy.”
It may be that those surveyed see the alternative energy sources such as wind and solar as green options. At the same time, many of the things they currently undertake do contribute to energy savings and less strain on the traditional power grid, it was noted.
Roerink saw what she called “successful energy management tactics currently being used such as lighting retrofits, replacement of older refrigeration systems, refrigerated case covers, skylights, staff training/awareness/accountability, and peak shaving.”
— Peter Powell
Publication date: 10/10/2011