This is due to the benefit of economizer
function in the new VC DX-DOAS design and more efficient operation at part-load conditions that occur particularly during cooler and drier times of the year.
One key consideration in this arrangement is the fact that the partial economizer
mode adds pressure drop above and beyond the original system design because flow must route through both a heat exchanger and a chiller in series.
The mechanical TXV was used as an expansion device of economizer
For each location, the incremental energy cost savings was found, arriving at a net present value of energy savings for the proposed water economizer
[S.sub.A], [S.sub.B], [S.sub.c], [S.sub.D]: The entropies of refrigerant at compressor inlet (KJ/kg*K), compressor outlet (KJ/kg*K), leaving the economizer
(KJ/kg*K), and vapor mixture (KJ/kg*K), respectively
This flux releases the useful output in the heat economizer
damper was configured to be manually controlled using a 2-10 V variable DC voltage source to the motor.
Today, new cooling system technology, particularly economizers
and supplemental cooling systems, are available to slash electricity bills substantially.
Due to other system inefficiencies we are currently addressing, the result of these air handlers entering economizer
mode is not necessarily less energy used by the system.
Without the Indirect/Direct Evaporative Cooling components a more conventional AHU (Figure 3), with an air side economizer
, will need to introduce 18,811 CFM (8,878.8 L/sec) of outdoor air to achieve the required 60[degrees]F (15.6[degrees]C) supply air DP and will require 68.96 Tons (242.5 KW) of refrigeration, a 26% increase in peak cooling demand.
The calibrated model developed by eQuest and discussed before is used for estimating the energy savings that could be resulted by implementing the C[O.sub.2]-based DCV along with the economizer
on heat pumps located in classroom and offices.
In order to evaluate those effects, both systems were operated in "continuous indoor fan operation without economizer
" and "synchronized indoor fan operation with economizer
" cases with three indoor set temperatures: 23[degrees]C, 25[degrees]C, and 27[degrees]C (73.4[degrees]F, 77[degrees]F, and 80.6[degrees]F).