Q. I have some questions about pumped glycol systems. What happens if all the entrapped air is not removed from the glycol? Should a closed loop have auto bleed? A. Air bubbles entrapped in the glycol circuit are very detrimental to the thermal performance of the energy recovery system. It causes the heat transfer… Read more »
Project: Millipore R&D Building Location: Bedford, MA Engineer: Parsons Contractor: Turner Construction Company Manufacturer: Strobic Air, Cambridgeport, Heat Pipe Technology Equipment: Energy Recovery Air Handling Units Size: (4) 30,000 CFM Units DAC Sales Engineer: Jim Shiminski Project Challenge: This was a new building project. The engineer, owner and contractor were all looking to create a… Read more »
Q. What is a typical pressure drop across the Konvekta coils? A. The air pressure drop across the coils depends on several factors: number of rows, air face velocity, fin spacing and tube alignments. There is a trade-off between thermal efficiency and air pressure drop which will be one of the design considerations if we… Read more »
Two years ago Rick McGinley and I were contacted by Rudolf Zaengerle from Konvekta. Konvekta had done research and had singled out DAC Sales as the firm to represent them in New England. Rick and I were not convinced that Pumped Glycol Run Around loops were viable. They had always been our least favorite means… Read more »
Q. Is it ok to turn an energy recovery wheel off for economizer purposes? A. No, we do not recommend that. If an energy recovery wheel is stopped it’s flutes can clog if filters are not maintained properly. The wheel is self cleaning as it rotates through opposite air streams. It needs to run at… Read more »
Frost control for any energy recovery device here in New England is typical. This post looks at heat pipes. With a building Exhaust Air of 68°F and 50% relative humidity, with typical air flows, a 6 row Heat Pipe will begin to frost when the Outside Air temperature is somewhere between 0° to 10°F. We… Read more »
Introduction: Many buildings require substantial amounts of outside air to be brought in through their ventilation systems. In many cases it is code ( schools) and in other cases it constitutes make up air for contaminated exhaust air (laboratories). Regardless, exhausting expensive conditioned indoor air and replacing it with outdoor air is really expensive. Energy… Read more »
A heat pipe is a thermal transfer device. It’s basically a sealed tube filled with refrigerant. It typically spans the supply air and exhaust air sides of a system. Energy is transferred – with no moving parts – from one air stream to the other (as long as there is a temperature difference). Refrigerant is… Read more »
Nearly once a week I am confronted with this question. My customer, “I have an application for Air-To-Air energy recovery. What type of energy recovery device should I use?” My answer is nearly always the same, “That depends”. We have several choices. All the technology has been around for long time now. Pumped glycol… Read more »