Dear All,
I'm a consultant engineer and need to design a hospital that treats cancer patients with nuclear medicine.
Here is a situation, I'm air-conditioning a LINAC Bunker rooms with once thru system. I've done all calculations and other heat load related stuff. Now the concern is about the...
Why are we calculating dehumidified cfm using sensible heat alone? Will the cfm be different when calculated using latent heat? And why coils are selected based only on inlet and outlet temperatures but NOT in relevance to humidity ratios? Why in design for comfort applications we always say...
Hello everyone,
I'm doing a comparison between DX inverter model machines and VRV/VRF sytem. I'm comparing in all terms, CapEx, OpEx, system performance, ease of operation, etc.
I'm in need of data like ikW/TR for DX inverter and VRF systems. Further to that, is it a good idea to compare the...
Hello All,
I have a situation where the result of heat load, which was done by a consultant, is 9000 CFM at 20 TR. The heat load summary is given below:
Sensible Heat Gain: 63 kW
Total Heat Gain: 70 kW (20 TR)
Dehumidified Air Quantity: 4250 L/s (9000 CFM)
Inside Design Conditions: 23+/-1 degC...
Hello Professionals,
According to heat load calculations, I'm getting 80 TR and 32800 dehumidified CFM for a subjected space, a shopping complex. The situation is I need to use only 4 TR cassette split units for the space. The cassette units are rated for 4 TR at 1140 CFM.
Now should I go for...
Hello All,
I just want to be certain on a few things while doing heat load calculation. Please do advise.
1. What is the significance of using "COOLING/HEATING DESIGN DAY and DESIGN MONTH conditions" over the "OCCURRENCE PERCENTAGE conditions" while selecting the outdoor weather data? Is the...
Hi All,
I'm having a meeting with architect to get inputs for our machining workshop air-conditioning project. I have a few points noted, but still I want to be confident during the meet. Would you please suggest few points and checklists that I need to ask him?
Hello Professionals,
I'm in need to calculate the cooling load of a portable container (18m x 7m) that is placed inside a completely shaded area. That is the container is placed inside a workshop. The workshop is roofed with corrugated metal sheet (w/o any insulation). Now, using HAP, I need to...
Hello Engineers,
I need to calculate the insulation thickness needed for CHW pipes and ducts. The operating range of temperature in pipes is 6 to 12 deg C and of ducts is air at 14 deg C. No return air ducts used in the system. The return is through ceiling plenum. It is mentioned in the...
Hello Professionals,
I was reading an article about car park ventilation. It was mentioned there are three methods to ventilate car parks.
(i) Open Sided Ventilation,
(ii) Natural Ventilation, and
(iii) Mechanical Ventilation.
I can understand that mechanical ventilation differs from the other...
Hello Professionals,
I have come across two methods to determine the frictional pressure drop of FITTINGS (Elbows, Tees, etc.) in chilled water piping. One is to use equivalent length of fittings and the other is by using the local frictional coefficient of fittings. Which one of these methods...
Hi all,
"By definition valve authority: it is the ratio of full flow pressure drop across the valve to the total pressure drop in the circuit (incl the valve). I also read that valve authority signifies the difference between inherent valve characteristics and installed (actual) valve...
Dear Engineers,
I read in a book where FAN HEAT GAIN is given by the formula:
Fan Heat Gain = Nameplate ShaftPower/Overall efficiency of motor+drive+fan.
I believed the heat gain to be a part of energy that is being lost due to inefficiency. In other words, "Power input*(1-overall...
Hi All,
I'm unable to figure out a "PARAMETER" in Door Opening force Calculation. I have the formula from ASHRAE and I can substitute values to find the answer. No problem in it. But there comes a parameter that I could NOT relate where it exactly appears on doors. The measurement "DISTANCE...
Dear Engineers,
I work as HVAC Design Engineer in a contracting company.
I wish to gain knowledge regarding chiller selections. Especially arriving the total number of chillers and total number of secondary pumps needed for a system.
I'm working on a commercial building project for office...
Hi Professionals,
I'm having few troubles in understanding the functioning of balancing valves.
Balancing valves are used to balance the flow among the load per design. We use static (manual) balancing valves in constant flow applications.
But, when it comes to the usage of dynamic...
Hi Professionals,
I am working on an HVAC system that requires hydronic piping. The tender specification calls me to use Sch 40 - Galvanized Iron pipe for the application. I need to size the pump. I am having flow rates for all pipe segments. The problem which I face is when using the friction...
Hi All,
I am aware of the definitions of PEAK load and BLOCK load. Would anyone please suggest me when to use peak load and when to use block load?
I am designing a commercial office building. The office has 16 systems. Each system has 12 zones and each zone has 2 space associated with it. I...
Dear Professionals,
I have struck up some where while working with Hourly Analysis Program in finding the COOLING LOAD for an Office.
Overview:
The system for the office is proposed to be a chilled water AHU (VFD driven fan in AHU) with VAV boxes. They need around 20 VAVs w/ thermostats in the...
Dear Friends,
I am designing an Office Space air-conditioning system with the following estimates:
Cooling Load : 25 Ton
Conditioned air flow into Office space: 10000 CFM
Fresh air supply: 1000 CFM (ambient air from outside for maintaining IAQ - added in the mixing plenum of the return air...
