According to Robur, the GAHP-AR is the first air-source water ammonia absorption heat pump.

When it comes to heat pump equipment, Richard Halbig, sales manager for Robur Corp., thinks that “The introduction of gas-fired absorption heat pumps to the heating and air conditioning industry has been the most profound product development in years.”

Currently, 20 percent of Robur’s business consists of heat pumps and the company typically sees application designs in conventional comfort conditioning of a residence or light commercial facility. With the growing interest in environmental and green issues, Robur is finding that end users are seemingly more interested in heat pumps and the applications are becoming more diverse.

“We anticipate a continued sales increase in 2009 and for the next several years,” said Halbig. “Since Robur heat pumps’ primary energy source is gas, market areas with high electric rates and reasonably priced natural gas will be our focus.”


As new products emerge and trends develop, Robur encourages technicians to continue to attend manufacturer-authorized training. When it comes to designing a geothermal heat pump system, however, Halbig recommends “The sizing and design for geothermal systems should be performed by a professional engineer or someone specifically trained in geothermal applications.”

The company is currently emphasizing its heat pump marketing push with its GAHP line that includes the AR and the W-LB series.

According to the company, the GAHP-AR is the first air-source water-ammonia absorption heat pump. By using natural gas as the primary energy source, it supplies hot water up to 140°F or chilled water down to 37.4°. The same unit can be used for heating or cooling by reversing the absorption cycle, using the outside air for heat rejection in cooling mode and as a heat source in heating mode.

“As a general efficiency feature in moderate climate areas (about twice the heating load hours versus cooling load hours), the gas savings during the heating season can offset the gas consumption normally required during the cooling season,” said the company.

The W-LB Series is a ground-source heat pump operating on a gas-fired water-ammonia absorption cycle.

“This unit combines the advantages of geothermal systems’ heat recovery with the advantages of gas-fired appliances,” said the company. “Foreseen for indoor installation, it is designed for heating-cooling applications with heat recovery from closed-loop or open-loop systems.”

In discussing applications of these products, Halbig said that electric heat pumps are commonly used in areas where comfort cooling is the predominant selection factor.

“Robur heat pumps, however, are better suited for applications - light commercial and large residential - where comfort heating and/or a high demand for hot water is predominant due to the company’s high heating efficiencies and considerably less dependence on back-up heat.”


Atypical applications are candidates for Robur heat pumps as well. A winery installation at the Cantina Selvapiana near Florence, Italy, utilized three GAHP-W gas absorption heat pumps for simultaneous production of hot and chilled water. These units were dedicated to the base load of the system. The installation also employed two AYF60-119/4 chiller-heaters to supplement the base load during peak demands for chilled and hot water. The goal was to satisfy both the comfort conditioning of the staff and provide the process chilled- and hot-water requirements during the winemaking process. The installation of the Robur equipment was part of an expansion project at the facility that included enlargement of the vinification cellar due to a new fermenting room equipped with stainless steel tanks, new aging barrels room, a new building used for the bottle cellar, one additional fermenting room for masonry tanks, and an equipment room and warehouse.

The total system requirements were 485,000 Btuh for heating and 25 tons for cooling. The premises, however, had very diverse heating and cooling needs. In the fermenting room, a precise control of temperature and humidity had to be maintained during the winemaking process. In the aging barrels room, a high humidity level was necessary. In the new fermenting room, a system to cool and heat the stainless steel tanks was required as well.

To satisfy all aspects of the winemaking process and comfort conditioning in the space, there was a requirement for simultaneous cooling and heating. The medium selected for this need, in all systems, was water. A four-pipe circuit was used for the winemaking processes, which require chilled and hot water simultaneously and a two-pipe circuit for the comfort conditioning, which can provide alternate cooling or heating.

The direct digital control (DDC) provided staging of the gas absorption units to allow for efficient operation. For example, the GAHP-W units provide hot and chilled water during normal operating periods. During high- demand periods, the AYF chiller-heater units are activated to provide any additional chilled and/or hot water that may be required.

“The Robur solution allowed the correct requirement of chilled and hot water to satisfy both the comfort load and the process load,” said the company. “This integrated system provided exceptional flexibility with a gas utilization efficiency variable from 1.86 to 2.25, keeping operating costs low.”

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Publication date: 05/25/2009