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The department of energy puts out a program that is a free download. It used to be called DOE2 but it may have been renamed to Visual DOE (I'm not sure what the newest version is called). A slightly more simplified version of the DOE2 program is called Equest, which is also free and is...

Have you checked Aerco boilers. I've used them before for condensing boilers, but I'm not sure about the dual fuel component.

Just as a added note, if you do use the fan approach where you are using 100% OA for cooling you should put a filter on the intake louver. I have used both methods for MCC rooms. In many cases if the air flow rates get too big and hence the louver sizes get too big because of the low delta T...

I have used both Carrier and Trace. The differences in the programs are in the menus and screens and the way you go about modeling your building as well as how the print outs look. I personally prefer the Carrier. I like the output pages. I feel the way the are organized it is easier to find...

Thanks guys for your input. I agree with you completely. I didn't find any design guidelines or literature for this type of facility. I do know that odor control is a big deal with this which is something that is not dealt with in human hospitals, but much beyond that if you know of any...

We have been paid by another mechanical engineering firm to review and ultimately stamp design drawings on project which is an Aminal Clinic. This building has a surgery room, isolation room, and special procedures. I've worked on many hospitals, but never one with animals and the codes (IMC...

The IMC states under "Mechanical Ventilation" that "Ventilation supply systems shall be designed to deliver the required rate of supply air to the occupied zone WITHIN an occupied space. Providing your code required ventilation air to another space (ie the corridor) defeats the whole point of...

Thank you for your responses. The application I am specifying for is an office building. The Sound Attenuator Rep who was helping me with the selection asked me what kind of DB levels I'm trying to achieve. And that's when I started to research this. I agree about the NC levels. When I size...

I'm trying to find some literature somewhere where I can find acceptable or recommended DBa levels for varous building types so that I have a basis for sizing Sound attenuators. I couldn't seem to find anything in ASHRAE and local codes do mention anything with respect to that. Anybody have any...

I've seen many base building projects where the main building design has VAV rooftop units and the supply distribution on each floor has the supply duct in a continuous loop around the floor. The return is a plenum return system. Can somebody tell me what the reasoning is for designing the...

cry22, How did you calculate your air changes without know the room volume ??

This might be a hard question to discuss without graphics, but I'll try. If I want to add a secondary pumping loop to an existing hot water system (due to remodeling of existing spaces) where this secondary loop will be for a new wing of VAV reheat. Does the return line for the secondary loop...

Can somebody give me a good explanation why typically when you size heating coils in VAV systems (either reheat coils for VAV boxes or in the VAV AHU) is it customary to size the coil for about 50% of the maximum (cooling) airflow rate. I usually see in the sequence of operation that when...

Its mostly an interior remodel so making changes to the AHU isn't really feasible. I'm guessing that they are constant volume mixing boxes because there is only one fan on the supply. The dual duct boxes they list on the equipment schedule are Agitair. Anyone ever hear of them. The equipment...

Well, the 3000 cfm is a the air flow for the existing space according to the design documents I was givin. I'm trying to reuse these Dual Duct boxes where ever I can in the new space renovation, but I want to make sure I don't exceed the total airflow that the ducts and the system can handle...

A project I'm working on is being served by a 40,000 cfm dual duct air handling system. This is my first time actually working on such a system. The Cold deck is sized as a 40" round duct and the hot deck is about a 36" round. Can someone tell me how you typically size the cold and hot decks...

You need one AHU sized for 100% of the load and another backup size for 50% of the load. That is the 50% redundancy. Sometimes owners want this because they don't want to pay for two 100% units, so they feel that if something should go wrong with the main unit that they can get by on 50%...

I'm sure this has been discussed several hundred times already, but here it goes anyway. I have an existing patient room that is being redesigned to be an isolation room that only needs to be negative some of the time, the rest of the time it can act as a patient room with neutral...

If I understand your question, you should at least have the LAT off the heating coil be 75-80 degrees F. If you don't need the AHU for heating because of the perimeter radiation then you should at least supply neutral air into the space when heating is called for. You don't want to be heating...

I can't say that I'm an expert in this area but there is an equation found in ASHRAE that might apply to this situation. DP = (Q/2610*A))^2. Where dp is the diffential pressure (0.1" in this case), Q is the cfm, A is the area of leakage. You can solve for Q to find the cfm, but you need to know...