Can somebody explain to me how or when a coil will freeze. More specifically, if I have a pre-heat coil, and even if the mixed air temperature entering the coil is below freezing, it seems to me that as long as the pump(s) are actively circulating hot water (160-180 Deg F) through the coil how...
What sequence of operation is best to use on the VAV box when you have a reheat coil.
One company I worked for had it customary to have the VAV box in maximum airflow setting when needing heating from the reheat coil. They would size the reheat coil based on the VAV box maximum airflow rate...
I think I posted this thread in the wrong place the first time.
I am designing a four story hotel with a commercial laundry room on the first floor.
We were given a prototype design to follow, but the problem is the prototype was designed for Atlanta and the hotel is located in Michigan. The...
I have a quick question. I have a hydronics Rep telling me to put the pressure relief valve of a hot water system containing a heater exchanger on the suction side of the pump (right after the expansion tank).
Is this philosophy correct. Shouldn't it be on the discharge side of the pump where...
For IEQ credit 5 in LEED 2009 "Indoor Chemical Source Control"
They require you to state what the average differential pressure is across a particular room.
ASHRAE lists a formula (Q=2610*A*√∆P) Which tells you the differential across a door, but does anyone know what LEED means when they...
I am trying to do some calculations on a spreadsheet on how much energy savings can be incurred by a building if they add Hot Water Reset controls to the boiler. During my internet searches for knowledge on the subject and hints on the calculations I came across an article that said there is an...
OK guys, I need some advice. I am designing a 3 story apartment building. Per the owners request we will have condensing boilers to heat the aparments via hot water fin tube. Cooling will be done with a "thru-the-window" AC unit. Each apartment has a local toilet exhaust fan interlocked...
Can some explain to me how to know when or where in a pipe run an expansion loop is necessary. I've seen a lot of literature on how to size an expansion loop, but haven't seen any explaining, where along the pipe run one is needed.
Thanks for your help.
I'm trying to gain a little more knowledge on hydronic systems and at the risk of asking something obvious, Can someone please explain to me why we typically fill a hot water system (or chilled water)from the bottom of the system and not the top. It seems that if you fill it from the top you...
What's the fastest velocity a return air transfer duct should be sized for. Or better yet how should transfer ducts be sized in general. If I have a central Roof top unit serving a three story building with a return air plenum and all the transfer ducts going from tennant space to tennant...
