Stand in front of the heat vents at the future law offices of Lear and Lear, and the warm blast feels just like the air coming from your furnace at home. You'd have no idea the heat was coming from the sewer.
Brothers Jon and Phil Lear, partners in the oil and gas law firm and co-owners of the historic home of Civil War veteran Maj. George Downey at 808 E. South Temple, are renovating the 1893 mansion into office space. Their work involves a fairly unusual idea — one they hope can be used elsewhere in the city, including developments such as City Creek Center, the The Church of Jesus Christ of Latter-day Saints' downtown mall project.
Heat-pump technology is not uncommon. The pumps concentrate heat energy absorbed from some heat source, usually the stable temperatures underground or from groundwater, and warm a cool room with it. In the summer, the pumps reverse, sucking the heat from a building and transferring it to the ground or passing water.
But as far as the Lears know, their project is one of the first to use sewage as that heat source in winter and as a heat receptacle in the summer. The only other similar system they've found is a housing development that opened last spring in Oslo, Norway, which operates on a larger scale and with slightly different technology.
The Salt Lake home, a seaside Victorian-style mansion modeled off homes in Bristol, England, was built at a cost of about $17,000. Downey served in battles such as Chancellorsville and Gettysburg, and after the war, he served as an infantry officer with assignments in California, Arizona, Idaho and Utah.
He retired in 1889 and came to Salt Lake City to serve as a principal of the Salt Lake Telephone and Telegraph Co. and the Commercial National Bank. He then had the home built, and it housed the Downey family into the 1920s.
Decades later, during the initial stages of renovating the home, Jon Lear came up with the idea of using heat pumps when Hurricane Katrina drove gas prices up. He met with an environmental engineer he knows, who recommended heat pumps as the most efficient option.
At first, the Lears wanted to use the city's culinary water system, but city officials nixed that idea. Drilling wells to tap into groundwater also proved ineffective.
It was during the Lears' discussions with city water officials, when Jon Lear was asking for permission to use a city water source, that one of them told him, "Use what you want — use the sewer — just not the culinary water," Jon Lear recalls. "I said, 'Hold that thought.'
"Being the first one of its kind, there's a higher learning curve with it," Lear said. But the pumps are up and running, and so far, "they seem to be doing what we intended them to do."
How it works
For heat pumps to function, the heat source doesn't actually have to be all that warm. Underground sewage rarely gets much hotter than 50 degrees, but that's warm enough.
Tubes carrying a pinkish heat-transfer liquid run through the currently unfinished walls and ceilings of the Downey mansion. To touch them, you would hardly think that at about 40 degrees they are warm enough to heat a room.
The liquid picks up that heat energy by running through an outer pipe installed around the smaller sewer lines. Neither the tubes nor the liquid they carry ever make actual contact with sewage.
To supplement the sewage, which is at a relatively low flow in front of the mansion, the Lears' system also uses ground heat and a 1,500-gallon basement water pool as heat sources. In the summer, the pool functions as a heat receptacle, or "sink," when the system is used for cooling, and the water from the pool can then be used to water the lawn.
The heating and cooling system, combined with the Lears' purchase through Rocky Mountain Power of wind-generated electricity, means the mansion is technically free of reliance on fossil fuel. The brothers joke that it's a sort of penance for their giving legal representation to oil and gas companies that seek to expand throughout the Intermountain West.
"We feel we're doing our part, as it were," Phil Lear said, estimating a yearly 6- to 7-ton reduction in carbon-dioxide emissions. "This is one way that we can kind of blend the green with the development and not burn as much."
The Lears estimate that the heating system cost about $20,000 more to install than a traditional one would have. Jon Lear said the ducting and heat pumps themselves weren't any more expensive than traditional furnaces and ducts. The added cost came mostly from hooking into the sewer line.
City Creek Center?
Jon Lear said that kind of infrastructure is just as expensive for users of natural gas and other traditional heating systems, but the traditional-source costs are covered by utilities that can afford it because the system creates future customers.
That circumstance puts people who want to use green technologies at a disadvantage, he said.
But the Lears can apply for a tax credit approved by the Legislature earlier this year to help offset the costs. The credit, an incentive to integrate renewable energy sources into homes and businesses, is good for 10 percent of the installation cost, up to $50,000.
Salt Lake City also pitched in to help the Lears. The City Council last fall approved giving $10,000 from the city's general fund to the project. The city considers it an experiment that could lead to similar systems being used elsewhere in the future.
One of those places could be the City Creek Center development. Jon Lear said he and Mayor Rocky Anderson have pitched the idea to planners with the LDS Church's real-estate arm, Property Reserve Inc.
PRI officials would not say how likely they are to adapt the Lears' idea to their project, although they said they are open to innovation.
"The City Creek project will utilize environmentally sensitive sustainable-design principles," PRI spokesman Dale Bills said. "Heat-transfer technologies are among a number of concepts we are reviewing."
Jon Lear said PRI's potential use of the technology could prove it works on different scales.
Essentially, a heat-pump system works by moving heat energy from one place to another — a "community technology," Jon Lear calls it. In a setting like a law office, that means moving heat from the sewer to the building and from room to room. In a mixed-use project like City Creek Center, that could mean from building to building.
Homes typically use most of their energy in the morning and the evening, sitting empty during the day while offices and commercial spaces become the major energy users. City Creek Center, with its mix of residential, office and commercial uses, would allow heat generated for a condo on a cold winter's morning to be reused in an office at noon, rather than going to waste.
That heat could come from a number of places — maybe the sewer, maybe the underground City Creek.
As for the city, the Lears believe the system could offer many benefits. While the entire city could probably never be on such a system — sewage has a finite amount of heat energy — it's a technology that could be interspersed throughout different developments and in different areas.
And because the heat is drawn from the city's sewer lines, the city could sell "thermal units" to homes and businesses that tap into the heat.
"We know it works, but if this becomes something beyond a pilot project, it has a number of potential benefits for the city," Phil Lear said.
E-mail: dsmeath@desnews.com