A basic HVAC system shows the application of the Second Law of Thermodynamics. The compressor adds energy to the refrigerant, and it becomes hot, just the way a hand operated tire pump does. Since the compressed refrigerant is hotter than the air blowing across the condenser, the heat will flow to the cooler air. This is a transfer of heat energy out of the refrigerant.
Thermodynamics, as with most concepts in science and physics, is most accurately described using mathematical equations. However, simple explanations, although not perfectly accurate, are sufficient to convey the information needed to understand everyday experiences. This article is an attempt to simplify these concepts.
Transpired solar air collector technology, developed at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) back in the 1990s, recently found its way back home and is now an integral part of the comfort heating system of the new Research Support Facility (RSF).
People sometimes ask if there are wear differences due to the raw edge design of the notched V-belt vs. the fabric all over design of the classical wrapped V-belt. The fact is many factors can contribute to sheave wear. However, notched V-belts and wrapped V-belts have virtually identical sheave wear characteristics.
Could the shift to better filters mean that they could cause problems with inadequate airflow or greater fan energy use? Are all high-MERV filters equal, or do some have less pressure drop than others? How much better are 2- and 4-inch-thick pleated filters than 1-inch filters? Some tests were run to answer these questions.
It is possible to ensure high-quality brazing connections in a safe and environmentally friendly way? Yes it is, with mixed oxyhydrogen gas generators. This technology works only with water and electricity. Gas is generated through a particular electrolytic cell, able to get H2-O2 from the water.
Ongoing
economic and indoor environmental concerns require HVAC innovation. New liquid desiccant air conditioning systems offer
substantial energy savings and greatly improved humidity control in
applications where latent loads (moisture) are very high relative to sensible
loads.
Moisture in building envelopes can have serious consequences. For example, moisture in insulation reduces its insulating capability, causing heating and/or cooling losses and wasting energy. Moisture can also cause structural deterioration and foster mold growth. Thermal imaging is well suited to identifying wet spots.
Smart HVAC equipment that recognizes when it is failing or has failed, or when conditions have drifted outside its optimum range, could save substantial amounts of energy if the equipment sent useful information to the building owner or contractor. This is referred to as automated fault detection and diagnostics (FDD).
While synchronous drives do have many industrial applications, they are generally not accepted as the best option for HVAC equipment. Virtually no OEM uses or recommends synchronous drives due to cost, noise and vibration, structural design concerns, and reliable availability of replacement components.
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