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Field Test Proves Older Systems Can Reap Savings With TXV, Too
No longer just a dire prediction, budget-breaking energy costs have arrived in the United States, long fortunate to have among the world's very lowest utility costs. Though the winter of 2007-08 was relatively mild in many areas, consumers were still beset by utility bills that increased by 50 percent and more over prior years. Further increases are happening - and have occurred - during this year's summer cooling season.
Pressed by federal regulations to improve energy efficiency by a measurable 30 percent, air conditioning system manufacturers redesigned hundreds of units in their product offerings to meet the new 13 SEER requirement, which became effective in January 2006.
In 2001, five years before the requirement was to go into effect, Danfoss began development of an expansion valve, type TR6, designed specifically to improve the efficiency of new residential air conditioning systems. Testing of the new valve on systems in both Danfoss and OEM laboratories showed that the improvement in efficiency over the fixed orifice devices previously in use was significant and would be a major contribution to meeting 13 SEER.
With further work by the manufacturer and OEM engineers, compliant new systems could be offered by the 2006 deadline at more reasonable prices than had been expected.
ADVANTAGES
The advantage of a thermostatic expansion valve (TXV) like the TR6 - over previously used fixed orifice regulation is that a fixed orifice device constantly delivers the same amount of refrigerant to the evaporator regardless of the living space load on the system. With a fixed orifice, when temperature is lowered to the desired level, then rises a bit, the system comes on and delivers the same maximum cooling that was required for...