Energy Stewardship
Save Energy, Reduce Air Pollution, Increase Profits
By Ken Williams
Energy Stewardship is an important political and social issue. It means reducing the energy a building consumes to provide a safe and productive environment. Using energy efficient and environmentally friendly heating/ventilating equipment is an easy way to make a big impact in this area. Energy stewardship does not need to come at a premium. Using direct gas-fired space heating equipment is one way to save energy, reduce air pollution and increase profits while doing it.
Direct Gas-Fired Space Heaters
Direct gas-fired heaters with high temperature rise, Blow-Thru® technology have been used to heat thousands of metal buildings. It is recognized as the most energy efficient way to heat insulated buildings that require ventilation. Typical applications include warehouses, assembly areas, boat storage facilities, aircraft hangars, car dealership service bay areas and indoor sports facilities.
Indirect gas-fired space heating equipment, like boilers, unit heaters, air turnover equipment and even tube-style infrared heaters require some method of heat transfer, such as a heat exchanger or radiant tubes, which lower energy efficiency. A flue is also required to vent products of combustion (and heat) outside the building. High performance, direct-fired heaters have gained popularity because there is no wasted energy. 100% of the available heat is delivered to the space because there are no flue or heat exchanger losses.
Not all direct-fired air heaters are alike. Three different types are used to heat/ventilate metal buildings as summarized in TABLE 1. Blow-Thru® Heaters have the burner downstream of the blower. This advanced technology provides superior comfort levels and improved indoor air quality with the least amount of energy usage. The Blow-Thru® design offers a higher BTU/CFM ratio and is available with the highest temperature rise/discharge temperature rating of 160°F. This crucial maximum rating results in smaller, but more powerful heating units. It also translates into lower horsepower motors, less outside air required to heat a building and lower energy costs. Conventional direct gasfired air heaters use a low temperature rise, draw-thru design where the blower is downstream of the burner. This older technology is used for both make-up air (MUA) and recirc heater (80/20 pressurization) type designs.
Save Energy
The energy used to heat a building is
a function of many variables. The
heater’s combustion efficiency is one
important factor but of equal importance
is how the heating system is installed
and used. For many commercial buildings,
it must provide both space heat
and temper the building’s air infiltration
and/or outside make-up air used for
ventilation. For example, an infrared
heater is an energy efficient way to spot
heat people in a small workspace.
However, mounting heights above 18
feet, air stratification, creating negative
air problems and cranking up the thermostat
to compensate for cold drafts will
dramatically increase the energy used
by an infrared heating system. Properly
applied Blow-Thru® Space Heaters can
achieve 40% to 70% energy savings
versus both indirect-fired heating systems
and draw-thru type direct-fired
heaters as summarized in TABLE 2.
Reduce Air Pollution
Energy savings also means a corresponding reduction in carbon dioxide (CO2) and other greenhouse gases that cause global warming. Burning 100 cubic feet of natural gas (1 therm of energy) creates 12 pounds of CO2. To put this in perspective, consider a 50,000 sq. ft. boat storage facility with a 37 ft. high ceiling in Chicago, IL. This metal building heated with indirect-fired unit heaters will burn 1.5 million cubic feet of natural gas per year (15,000 therms) and put 88 tons of CO2 in the atmosphere. The use of Blow-Thru® Space Heaters to heat/ventilate the same building can reduce energy usage by 50% and prevent 44 tons of CO2 from going into the atmosphere each year. That’s the same as planting 132 new trees each year or taking 8 cars off the road.
Increase Profits
Developers and building owners understand the total cost to heat a building includes “first installed costs”, “operating costs” and “impact costs”. Blow-Thru® Technology is used to heat buildings from 5,000 to over 3 million square feet. Often the cost to purchase and install direct-fired Blow-Thru® Heaters is lower than using less efficient indirect-fired heating systems.
Energy efficient, Blow-Thru® Heaters use less gas and are virtually maintenance free so operating costs are low. That 50,000 sq. ft. boat storage facility in Chicago with unit heaters has an operating cost of $.30/sq. ft. (at $1.00/therm).Blow-Thru® Heaters using 50% less fuel means an operating cost of only $.15/sq. ft. with annual savings (increased profits) of $7500, or $75,000 over ten years. Developers are now promoting “high performance”, energy efficient buildings with direct-fired Blow- Thru® Space Heaters for just this reason.
Impact costs are more difficult to quantify. However, infrared heaters and air recirculating type-heating systems that do not provide enough fresh outside air to assure good IAQ or prevent negative air problems will adversely impact the everyday use of a building. Non-recirculating, Blow-Thru® Space heaters are equipped to deal with these problems because they use 100% fresh outside air.
Conclusion
So why doesn’t everyone use direct gas-fired Blow-Thru® technology to heat/ventilate metal buildings used as warehouses, boat storage facilities, aircraft hangars, automobile service areas and indoor sports facilities? Maybe it’s because old habits are hard to break, like not conserving our planet’s natural resources and polluting the atmosphere. No matter the reason, it’s never too late to consider energy stewardship as a way to save energy, reduce air pollution and oh yeah, increase your profits while doing it.