Dehumidification and reheat capabilities are among the most useful new advances in the geothermal arena, according to Joel Sigman, president, indoor climate solutions division, Sigman Heating and Air Conditioning/Sigman Indoor Climate Solutions LLC, Belleville, IL.
"Geothermal technology is already the most efficient way to heat and cool a space, and a reheat feature on a geothermal unit allows you to heat the water in a swimming pool, or dehumidify spaces such as indoor swimming pools or spaces in which artwork or other valuables will be stored, virtually for free," Sigman says. (See a sample Sigman project at http://bit.ly/sigmanprojectcb)
Variable-speed motors and two-stage compressors also have been welcome options for geothermal system designers to present to potential customers, Sigman says, and the addition of tin-coated coils to some manufacturers' product lines should help improve the longevity of coils by protecting them from damage caused by indoor air quality hazards, such as volatile organic compounds (VOCs).
Sigman adds that one of the biggest drivers in the geothermal market right now is the green movement — as in the green money that customers can save thanks to the 30% tax credit that's available for geothermal units through 2016. "The geothermal industry often talks about the importance of customer education, and a 30% tax credit is certainly one fact about geothermal that your customers really need to know," he says.
On Sigman's wish list: control panels that would allow service technicians to proactively analyze a unit or system and identify when it isn't functioning properly — before a breakdown occurs. "I know it's possible, because they have that type of capability on the commercial side," Sigman says. "I'm looking for someone to figure out how to cost-effectively bring it to the residential market."
High velocity systems are benefitting from variable air volume speed blowers and zone controls, according to George Gittinger, Design/Build manager, TUDI Mechanical Systems, Pittsburgh, PA.
"It's a big plus to be able to put multiple thermostat zones on one high velocity system," Gittinger says.
He adds that TUDI is beginning to combine high velocity and geothermal systems for some high-end homeowners, especially those who live in historic homes.
"The combination of geothermal and high velocity is great for these homes," Gittinger says. "Inside, they don't have a lot of room for ductwork. The small duct openings are perfect for maintaining historic character. Outside, they don't want equipment that will distract from the aesthetics of the house. It's a nice solution, inside and outside."
Customer education is an important element of the high velocity business, Gittinger adds. He advises educating potential customers about the effect of aspiration.
"Customers look at a 2-in. round hole in the ceiling blowing straight down, or in the floor blowing straight up, and they can't image how the conditioned air is going to circulate into the center of the room. But because it's moving at such a high velocity, even a small air stream aspirates or entrains the air around it and creates an air movement to involve the whole room," he says.
Customers may also be interested to learn that high velocity systems, such as SpacePak, are often better humidity removers than traditional systems, according to Gittinger.
"The coils are a little thicker and a little colder in a high velocity system than in a traditional system, and they actually have a little bit less air passing over," he says. "In essence, that gives them a better dehumidification capability."
Hybrid systems can take many forms, and the term can refer to pre-packaged units that combine two technologies, or custom designed systems made up of a combination of forced air, hydronics, geothermal, and any other HVAC technologies that a contractor applies to solve a comfort challenge in a highly efficient way.
At 72 Degrees Heating & Air Conditioning, Sanford, NC, Operations Manager David Vinson prefers hybrids that combine a heat pump and a gas furnace. Such systems, he says, can reduce customers' heating costs by up to 60%, especially if customers are using propane for wintertime heating.
"Obviously the cost of electricity is cheaper during the wintertime than the rising cost of propane," Vinson says. "The price of a hybrid system isn’t much higher than the price of either a furnace or heat pump alone. There are a few extra controls with a hybrid system, but otherwise there's not a huge cost difference. That makes the payback period for the homeowner pretty short."
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Although hybrid systems have become simpler to install and service, Vinson still advises additional training for technicians who are going to specialize in these systems. "The hybrid systems are different enough from a stand-alone heat pump or stand-alone furnace that you want to make that investment in training," he says.
The technology used to control hybrid systems is where Vinson has seen the biggest advances in the past 20 years. "We can now use digital thermostats to control a hybrid (dual-fuel) system. This gives us a lot of options to customize each systems' operation to meet our clients' individual needs. In the past, we used mechanical controls that had calibration problems and generally a short life expectancy."
High efficiency boilers have hel-ed make radiant systems more efficient than ever, while maintaining the comfort for which they're famous, says Joe Waskiewicz, co-owner, JV Mechanical Contractors, Inc. Webster, MA.
"Radiant is more expensive to install than a conventional system, but the investment that customers make is valuable, not only as far as their comfort, but also when it comes time to sell the house," Waskiewicz says.
"The controls on radiant systems are very versatile," he adds. "It's a great asset to be able to ramp a radiant systems up and down proportionately based on outdoor temperatures. You don't need to have 180F water constantly circulating through the system like you do with a baseboard heater or panel radiator."
Waskiewicz says radiant system efficiency is related to the equipment attached to it, so he doesn't install a radiant system if a customer's boiler is more than 10 years old.
"When we educate our customers about the advances that have been made in boilers in the past decade, they understand why," he says. Radiant systems will benefit from an influx of technology from Europe, according to Waskiewicz. "We're 20 years behind the European way of doing things," he says.
"The controls are the big thing, along with variable speed pumps and modular pumping stations. The technology in hydronics is changing quite drastically, and now that this technology is being introduced into this country, an increasing number of contractors and technicians are seeing that radiant systems are simpler to install, easier to maintain, and more efficient than ever before." (Read an Uponor whitepaper on radiant at http://bit.ly/radiantwhitepaper.)
Solar heating systems are still a tough sell in the residential market, but solar water heating is poised to take off, as America’s awareness of the need for energy efficiency grows, says Harrison Smith, president, Harrison’s Heating and Air Conditioning, Inc. Redwood City, CA.
"We offer solar water heating systems intended to supplement space heating, but we haven't had any takers to date," Smith says. "In general, everybody's excited about photovoltaic, but solar thermal is a tougher sell."
Smith attributes this to photovoltaics' ability to produce more energy than customers use, enabling them to sell some power back to the grid. "Although you could produce more heat than you use in solar thermal, you've usually got nowhere to put it, and certainly no way to sell the energy to others,” he says. "It limits the payoff period."
Technological advances include corrugated stainless steel tubing, differential temperature controllers, and dataloggers.
"The corrugated stainless steel tubing, although it's one of the simplest things, is probably one of the most helpful products in the solar industry. It just saves a lot of work," Smith says. "There are also a lot of great controllers out there. It would be nice to integrate more of those, so that people can interface with some of the 'bells and whistles' that they can get with photovoltaics, and see graphically what they’re saving as the system is operating."
Smith's wish — an uncommon one — is for mandates and building code changes requiring some degree of solar water heating.
"Those requirements would help things along in this industry," he says. "I'd love to see more jurisdictions requiring solar water heating. In the long run, it would save a lot of energy, and bring this industry'’s costs down. Coming from a solar water heating installer that sounds a bit self-serving, but I think it should be a no-brainer to pre-heat your water with the sun."