Back to the air temperature readings, could it be the air coming off your heating coil was not well mixed, where your temperature probe was located, and when you measured 83F, that is not representative of a fully mixed condition. The further away from the coil, the more thorough the mixing...
That is a large temp drop for the conditions you describe. When you say you measured air temp in the diffuser neck, be sure you are out of the induction zone of the diffuser. Are the 3 air temperatures being read simultaneously using three (at least rough) calibrated measurement devices? It...
It sounds feasible though I've not heard of this particular situation that you describe. As I'm sure you are aware, there may be other mechanisms by which soot and other contaminants can be deposited on the furnace heat exhchanger and in the ductwork (EG. combustion products from household or...
As far as i am aware there is nothing like this in commercial HVAC use for thermal environmental temperature control. The typical operating temperatures and pressures and associated thermodynamics favoring this type of system would be in a different range than seen in typical people/process...
If you don't know the design air flows or have any way to measure the flow rate, then you normally would balance by temperature. Use a thermometer, and crank up the thermostat. If by some stroke of luck, all rooms experience the same temperature when the furnace is heating or cooling, then the...
You are correct, and rkostynu's advice is also on target. Keeping full steam pressure on the coil helps to keep the coil free of liquid (which could freeze) by keeping the maximum pressure available for operation of the trap. If you were to modulate steam flow, and by inference coil pressure due...
Now if the duct or conduit in which this mixture flows has an interior surface temperature below the air mixture dewpoint temp, then you will condense on the surface. I think you already know that though. ;)
From the old Carrier Handbook of AC Design, Part 3, Chapter 2 Table 14, they list a maximum water velocity to minimize erosion of 12 fps at 1500 hr/yr. So you are probably ok, as long as your water is not too nasty. Maybe you could compare heavier wall thickness 16" pipe to cost of standard...
In theory, as long as you remain to the right of the saturation curve you should not have condensation. In reality though, mixing is not an instantaneous and homogeneous process, so there may be some localized condensation, such as you see with the water vapor plume off a power plant stack. You...
Imok2 - Okay I'm taking the turkey off the table till this is resolved! If you are looking at rules of thumb for sizing tonnage for residential ac units, then the guidelines in the link you provided are applicable. The link recommends the typical range of cfm per square foot for residential ac...
Imok2 and Cubsfan - as far as reading different material, I try not to read too much... rather I'm going more from memory, and my memory gets foggy sometimes. Sounds like we have 2 votes for 400+ cfm/ton and 2 votes for 300-350 cfm/ton for residential applications. We need some tiebreakers to...
This thread has been discussed somewhat recently, and the "rule of thumb" varies widely depending upon cooling application. I agree that a load calc should be used, however for residential applications i think 300-350 cfm per ton is more in the ballpark. 400-450 cfm per ton is for very...
Gnordo - Is stainless steel inherently less susceptible to algae formation than say a galvanized or painted steel drain pan? If so, why is that the case?
Suggest you try the ASPE Guide and Data Books (sp). I believe they would have more relevant information on Potable Water System Design than ASHRAE Handbooks.
You can determine this from a psychrometric chart. Determine the entering and leaving enthalpy of the air stream at 77F and 70F. Also determine the mass flow of air by using the density from the psychrometric chart. Mass flow times enthalpy difference gives you heat removal rate required for...
You don't say whether your light manufacturing space is only ventilated or ventilated and air conditioned. Also the term air changes per hour frequently is referring to air changes per hour of outdoor air (ASHRAE 62 uses this), but also is used in reference to number of air changes or air...
The answer to this question depends more on the expected operating profile of the fan system and so there is no one answer that is correct. I don't know a lot about adjustable pitch axial fans, but do know they are highly efficient. If your fan system spends much time at 75-100 percent of design...
From the above responses, it sounds like for some manufacturers, elastomeric gaskets gradually replaced the metal push nipple method. Is this correct? Did all manufacturer's try the elastomeric gasket approach, and did some stick with it and others return to the push nipple approach due to bad...
I would be very surprised if the ERV is connected to bearing failure, unless the ERV flow is being directly injected into the fan cabinet section of the AHU, causing flow imbalance through the wheel. If that is the case, then when the ERV is operating there should be a measurable increase in fan...
