{"id":4455,"date":"2018-12-07T22:07:40","date_gmt":"2018-12-07T22:07:40","guid":{"rendered":"https:\/\/informatech.energir.com\/?p=4455"},"modified":"2021-04-16T08:36:28","modified_gmt":"2021-04-16T13:36:28","slug":"change-is-in-the-air-with-natural-gas-condensing-make-up-air-units","status":"publish","type":"post","link":"https:\/\/dev.informatech.colpron.com\/?p=4455&lang=en","title":{"rendered":"Change is in the air\u2014with natural gas condensing make-up air units"},"content":{"rendered":"

People are giving more and more attention to the fresh air needs of buildings—they’re concerned about health, and about the costs as well. Several factors are encouraging more efficient appliances, like natural gas condensing make-up air units, to emerge onto the market. Several factors are encouraging more efficient equipments, like natural gas condensing make-up air units, to emerge onto the market. The factors include the recommendations of ASHRAE Standard 62.1 (Ventilation for Acceptable Indoor Air Quality); the use of Variable Refrigerant Flow (VRF) systems in which a separate make-up air unit is normally required; and the increasing awareness of building owners, managers and users about the importance of air quality.<\/span>
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\nEliminating barriers<\/span>
\nWhile indirect-fired make-up air units have an efficiency of approximately 80%, condensing units have upwards of 90% efficiency. Despite their higher performance, however, these equipments are taking time to break into the market. Likely deterrents include a high initial purchase price and the risk of the condensate freezing in cold weather.<\/span>
\nThrough Énergir’s Innovation Program, Bousquet, one of Quebec’s largest HVAC equipment manufacturers, compared the on-site energy performance of a number of generations of make-up air units equipped with different heat exchangers, including a condensing heat exchanger. The results spoke for themselves: not only did the condensing unit prove to be more efficient, but any fears about using these equipments were dispelled.<\/span>
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Image 1: First, second and third generation (condensing) make-up air units (shown from left to right)<\/figcaption><\/figure>\n 
\nIntegrating technologies<\/span>
\nThe tested condensing make-up air unit has a new heat exchanger with dimpled tubes and a larger surface that reduces static pressure by 30% compared with conventional heat exchangers. The greater surface results in improved hot air flow, while the dimpled tubes allow for a higher rate of heat transfer. The new condensing heat exchanger also works in a variable air volume (VAV) system. Finally, its parallel flow system prevents condensate from freezing (see image 2), even at very low temperatures. Furthermore, because the unit is controlled by a programmable logic controller (PLC), it is easy and quick to start up.<\/span>
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Image 2: Freeze protection system<\/figcaption><\/figure>\n 
\nFull-scale testing<\/span>
\nTo demonstrate the benefits of its natural gas condensing heat exchanger, Bousquet wanted to compare its performance with that of older generation equipments. With this in mind, the company approached Énergir to carry out testing through the Innovation Program, which offers grants for innovative energy solutions (see sidebar). Following consultation, a trial was conducted under real conditions. The Natural Gas Technologies Centre (NGTC) was tasked with metering three generations of make-up air units, to compare their performances. The main objectives of the metering were as follows:<\/span><\/p>\n