Photo courtesy Cambridge Engineering
Summary and recommendations
HTHV direct-fired heating equipment can supply both ventilation and space-heating airflow to maintain comfortable conditions for occupants in commercial and industrial buildings. By bringing in outside air, direct-fired equipment does not increase the amount of air entering the building—rather, the airflow brought in by the direct-fired equipment creates a slight positive pressurization and offsets the infiltration that would normally enter through building seams. Through this method, the amount of air entering the building and the related infiltration heat load remains the same. Ventilation-only products, often called make-up air units, replace exhaust air by conditioning outdoor air only to indoor ambient temperatures, and thus require a separate space-heating system to satisfy the conduction heating load of the building. HTHV direct-fired space-heating products supply outdoor air at sufficiently high temperatures to not only supply heated ventilation air, but also satisfy conduction heating loads.
If deployed widely, HTHV gas heaters would significantly decrease natural gas consumption related to space-heating and ventilation for high bay areas such as warehouses, loading areas, distribution centers, and manufacturing facilities. Depending on the exact configuration, HTHV technologies could save 20 percent or more in space-heating energy consumption and utility costs as shown in the field demonstration and EnergyPlus energy modeling. (For more information, see Roger Hedrick’s article, “Energy Performance Comparison of Warehouse Heating Systems,” published in Gard Analytics. View it here www.cambridge-eng.com/Portals/0/pdf/gard-report.pdf). When used to both heat and ventilate spaces, installation cost savings can be achieved by serving the functions of heating, ventilation, and destratification.
Increasing the adoption of HTHV heaters will require a change in the way HVAC contractors, the ASHRAE community of engineers, utilities, and building owners and operators consider non-centralized heating equipment. Proper education on the availability and the potential lifetime energy savings of these technologies may encourage more industry professionals to evaluate HTHV gas heaters for their buildings, and determine whether the systems offer an acceptable payback based on climate, operations, and building design.
The following actions could further support the adoption of HTHV technologies.
Building owners should:
- perform a feasibility study on existing buildings to determine if retrofitting with HTHV technologies would provide acceptable payback; and
- consider upgrading their new construction best practices to incorporate HTHV technologies into their various designs for heating, ventilation, and destratification.
Natural gas utilities should:
- educate commercial customers and internal teams on the lifecycle cost of HTHV heating technologies; and
- include HTHV heating technologies in available grant, incentive, or financing programs.
Rebates
Building owners and facility managers can receive an additional gas utility rebate when purchasing and installing HTHV technology. For years, both electric and natural gas utilities have offered rebates for energy-efficient products ranging from light-emitting diode (LED) lighting to high-efficiency direct gas fired HTHV equipment. For more than a decade, natural gas utilities across the country have been providing custom rebates for HTHV products through their commercial and industrial rebate programs.
Since the DOE has provided solid data via their study on HTHV equipment, many natural gas utilities are adding prescriptive rebates for HTHV products to their commercial and industrial programs. Every month, more and more utilities join the movement and add a prescriptive rebate to their portfolios, thereby making it easier, and more cost effective, to install HTHV technology. The prescriptive rebate amounts can vary by utility. Some offer a set rebate amount for all the different Btu sizes available, while others offer a $3 or $4 per 1000 Btu rebate to help incentivize the purchase of even the largest heaters available. The later rebates can provide as much as $12,800 in rebate funding for a $3.2-million Btu heater.
These rebates, combined with the gas savings that a 92 percent efficiency HTHV heater provides, can help drive down the return on investment (ROI) that today’s building owners and facility managers are required to meet when purchasing capital equipment.
Conclusion
Adoption of energy-efficient technologies such as HTHV can provide significant progress in meeting the goals of the Better Buildings Alliance and will result in overall improvement and growth in heating technology efficiency percentages. As more end-users realize the energy savings and additional ROI available via utility rebates, these technologies will become the norm rather than the exception, helping drive down energy waste and cost within the commercial and industrial sectors.
Marc Braun is the executive vice president of sales and marketing for Cambridge Engineering. Braun holds a bachelor of science in chemical engineering and started his career with Dow Chemical 22 years ago. He joined Cambridge Engineering in the high-efficiency HVAC market six years ago as their chief operating officer and now travels North America speaking to engineers, building owners, and utilities companies on next generation heating and ventilation technologies. He can be reached at mbraun@cambridge-eng.com.
