Microprocessor Can Decrease Energy Bills
Fortunately, the computer revolution has come to the rescue of energy users. One of the "rescue technologies" is the Beckett HeatManagerâ„¢, a microprocessor-based control for residential and light commercial oil, gas, or propane hydronic heating systems. It's available in four models to accommodate a wide range of hydronic heating applications. The HeatManager is designed to accurately match the heat output of the boiler to the system's actual heat load, saving fuel.
The Science Behind It"During these times of high oil prices, customers are eager to save on energy costs," said David Cohen, executive vice president and general manager for Standard Oil, Bridgeport, Conn. "We have found the HeatManager to be a unique and effective way to acquire and retain customers."
His company, founded as a coal dealer in 1913, became an oil heating company after World War II, and is now a major independent oil company in Connecticut. The company has tested the HeatManager and documented the savings as high as 20 percent during spring and fall when the oversizing of the boiler is most apparent.
In the past, money and fuel were too often wasted on a yearly basis because of the difficulty in choosing the right capacity boiler. A residential or commercial boiler must be just the right size if it is to provide enough heat to overcome the very coldest anticipated outdoor temperatures. Because these extreme temperatures are rare, however, the boiler usually produces more heat than necessary.
As a result, the thermostat keeps cycling the boiler on and off to maintain home or facility comfort and prevent the boiler from overheating. This overcycling is inefficient; it wastes fuel and money.
The heat load is the rate at which a home or facility loses heat to the outside environment. In order to maintain comfort, a boiler must replenish this heat at the same rate at which it is being lost. The HeatManager allows the boiler to provide the right amount of heat in a more fuel-efficient manner.
By adding computer intelligence to the boiler, HeatManager reduces heating fuel usage by 10 percent to 20 percent, while reducing wear and tear on boilers by eliminating excessive on and off cycling.
Residential TestsThis approach works even under the challenge of frosty Canada. Ron Samson, manager of Kerr Controls in Newfoundland, is a HeatManager distributor. He decided to put his product to the test in his own six-year-old home to see if he could control the unnecessary starting of his boiler. His system is a fairly efficient, multi-zone, oil-fired hydronic heating system. "I chose the HeatManager so I could control and stabilize the firing of my boiler," he explained.
He saved upwards of 20 percent in home heating costs, moving from 2,592 liters of fuel oil a year (682 gal.) to 2,103 liters (553 gal.) a year. "The HeatManager control paid for itself in one year," said Samson. "I may work for Kerr, a HeatManager distributor, but even if I worked for the government purchasing shovels, I'd say the same thing. Any homeowner would benefit from this."
Glenn Dickey, president of Marshall Oil, Skippack, Pa., conducted a study confirming Samson's results. Dickey tracked before and after fuel use for five residences with HeatManagers. He then used heating degree-days to normalize the data. His study found an average 18 percent fuel usage reduction.
How It Works - The DetailsThe HeatManager uses a single strap-on temperature sensor attached to the boiler supply (outflow) pipe to measure the boiler water temperature (See Figure 1). Each time the boiler shuts off, either due to high limit or end of heat call, the sensor measures the rate that the boiler water temperature is declining. This rate is a direct representation of the heat load. A fast temperature drop of the boiler water directly corresponds to a heavy heat load, and a slow temperature drop directly corresponds to a light heat load (See Figure 2).
At the next call for heat, the HeatManager determines if there is enough residual heat left from the previous heating cycle to keep up with the measured heat load. If the HeatManager detects excess heat, it will delay burner firing, allowing the preheated water in the boiler to circulate. Only when the boiler water temperature is no longer sufficient to sustain the heat load will the HeatManager allow burner firing.
Easier Installation And ServiceThe HeatManager can typically be installed by a heating professional in 15 to 45 minutes, with no programming or follow-up visits necessary. There is no owner maintenance needed. To facilitate service, the compact (4" H x 4" W x 2-1/2" D) HeatManager displays operating modes and diagnostics.
The unit is installed electrically in a series between the boiler control and the burner, downstream of any limit relays. To do this, it is necessary to break the connection between the boiler control and the burner. The yellow and red wires from the HeatManager are used for interrupting this connection, which is the most critical connection when installing. The yellow wire from the HeatManager connects to the burner control terminal (B1) on the aquastat or limit relay. The red wire from the HeatManager connects to the hot lead on the burner. Other connections depend on the power and control voltage of the specific installation. According to the company, not only is HeatManager installation fast and easy, but it is also backed by a five-year warranty.
Additional schematics and other information on the HeatManager are available on the Beckett training module at www.becketthm.com.
Publication date: 11/28/2005