Lc_shi
09-12-2005, 03:50 AM
Dear sirs,
I've a design on hand for a total fresh air handler.
#Design paremeters as below:
--The inlet air DB is 29degree celsius,humidity 19g/kgdryair
--the outlet air DB 18 degree celsius,humidity is 6.8g/kgdryair
--air volume is 650m3/h
**The system is going to be designed as one compressor\DX coil (for dehumidifying inlet air)\evaporative condenser\reheating coil\hot gas bypass valve etc.
**the process is inlet air --DX coil(to machine dewpoint 9.88C RH90%)--reheating coil (to 18C,humidity unchanged)--to required space
When the inlet air enthalpy is lower than designed condition,the DX coil load is less ,so the bypass valve open and keep the evap pressure head not down.
my concerns are:
--if the DX coil load is reducing,bypass valve can keep the evap temp constant? if no,how to do?
--if the compressor is constant volume type, the bypass valve can play the role to adjust compressor capacity to meet the DX load?
--reheating coil is parellel to evaporative condenser,the heating capacity is changed while machine dewpoint is varied with the inlet air paremeters,i don't want make the control too complex,is on/off control (EM valve for the coil)reasonable?
--how do you think what the best system for this total fresh air handler?
welcome any comment
best regards
LC-:)
I've a design on hand for a total fresh air handler.
#Design paremeters as below:
--The inlet air DB is 29degree celsius,humidity 19g/kgdryair
--the outlet air DB 18 degree celsius,humidity is 6.8g/kgdryair
--air volume is 650m3/h
**The system is going to be designed as one compressor\DX coil (for dehumidifying inlet air)\evaporative condenser\reheating coil\hot gas bypass valve etc.
**the process is inlet air --DX coil(to machine dewpoint 9.88C RH90%)--reheating coil (to 18C,humidity unchanged)--to required space
When the inlet air enthalpy is lower than designed condition,the DX coil load is less ,so the bypass valve open and keep the evap pressure head not down.
my concerns are:
--if the DX coil load is reducing,bypass valve can keep the evap temp constant? if no,how to do?
--if the compressor is constant volume type, the bypass valve can play the role to adjust compressor capacity to meet the DX load?
--reheating coil is parellel to evaporative condenser,the heating capacity is changed while machine dewpoint is varied with the inlet air paremeters,i don't want make the control too complex,is on/off control (EM valve for the coil)reasonable?
--how do you think what the best system for this total fresh air handler?
welcome any comment
best regards
LC-:)