Manual balancing with calibrated balancing valves (CBVs) offers few benefits other than a small improvement in controllability for valves closest to the pump and the CBVs are useful on small, low pressure drop coils (such as reheat coils
) for diagnosing problems that may arise in the future.
They added refrigeration equipment with reheat coils
to solve the problems.
Most of the time, at least one of the suites will be conditioned without reheat, while the remainder of the suites may require local reheat coils
to maintain space dry-bulb temperature at the appropriate level.
The fan electrical power will eventually convert to the sensible heat and heat up the secondary mixed air ma2, thermally the same as the reheating load at the reheat coil
. Because both the supply fan and reheat coil
will not add or remove the moisture, the supply air sa condition after the reheat coil
of the TB can be expressed as
From the AHU, the supply air flows through a heat exchanger block (i.e., reheat coil
) with a constant effectiveness.
An important benefit of the cycle variant and equipment modifications is augmented dehumidification capability, due to lower evaporation temperatures, that could be used in humid climate zones to replace the reheat coil
methodology, giving further energy savings and equipment cost reduction.
Consider placing a single strainer for reheat systems in a location that is easily accessible as opposed to placing strainers on each reheat coil
in the ceiling space.
Figure 3a and 3b show the excitation signals for supply air flow setpoint and reheat coil
valve position, respectively.
Each air-handling unit was modified with a reheat coil
supplied with 80[degrees]F (27[degrees]C) process water waste heat to reheat air from 60[degrees]F (15.6[degrees]C) to 76[degrees]F (24.4[degrees]C).
Methodology for Splitting Fan Energy Use for Heating and Cooling Case Zone Mode Fan Energy Consumption Case 1 [E.sub.Reheat Coilx] = 0 Cooling (Evaluated for each zone) (For Zonex) Case 2 [E.sub.Reheat Coilx] > 0 Heating (Evaluated for Each Zone) (For Zonex) [E.sub.reheat Coil1...n] = Reheat coil
energy consumption Table 4.
This system uses a central DX cooling system with modulating hot gas reheat providing full condensing at an indoor reheat coil
. It is based on either a single-speed or a two-speed AC unit depending on the HERS level.
A discussion of the minimum outside air portion of the two fan dual duct system, the function of the air-handling unit warm deck heating coil and terminal reheat coil
will follow later after the establishment of the energy use advantages of the system.