Colin Goode, Fujitsu
One of the most frequent questions we are asked by contractors is, “what size and type of air conditioning system do I need for this job?” This is usually accompanied by a rough drawing of the space to be air conditioned and a few measurements. I suspect that distributors get asked this question even more than we do.
By Colin Goode, Fujitsu’s Product and Specification Manager
While we are always happy to give technical assistance to anyone who needs it, the fact is that the best person to make the necessary calculations is the one who has surveyed the building and knows the client’s requirements; in other words the system designer or installer.
By Colin Goode, Fujitsu’s Product and Specification Manager
While we are always happy to give technical assistance to anyone who needs it, the fact is that the best person to make the necessary calculations is the one who has surveyed the building and knows the client’s requirements; in other words the system designer or installer.
Rules of Thumb
There are some rules of thumb that many people use, such as 100, 120 or 130Watts/m2 for cooling. These still hold good for small rooms, standard offices and for a budget quote, but for a more accurate solution a recognised software programme should be used.
Accurately estimating the cooling /heating loads for every application is a fundamental design requirement of every heating and cooling project. This is vital to prevent over or under sizing of equipment and is something that should be done by the contractor or the person responsible for the overall system design.
In other words, there is no point in installing an Airstage VRII when a JIIS will do the job more efficiently, or installing a split where a VRF is needed. This will ultimately lead to customer disappointment.
Accurately estimating the cooling /heating loads for every application is a fundamental design requirement of every heating and cooling project. This is vital to prevent over or under sizing of equipment and is something that should be done by the contractor or the person responsible for the overall system design.
In other words, there is no point in installing an Airstage VRII when a JIIS will do the job more efficiently, or installing a split where a VRF is needed. This will ultimately lead to customer disappointment.
Calculating the loads
Fujitsu's Design Simulator To accurately calculate the heating/cooling loads, detailed drawings and/or a site survey is required and the following information obtained: size of room(s), occupation levels, internal equipment heat gains, orientation of building/room, area and type of glazing/shading, wall/ceiling/floor/roof construction, existing or required ventilation rates, ceiling void space, location of existing power supplies, space for new equipment and anything else that may be useful to assist with the proposed design.
There are many load estimating software packages available. Some relatively simple free calculators can be found on the internet but any self-respecting contractor or designer should purchase something more sophisticated, such as AC Calc by Click Software, which uses industry recognised methods to model old and new building types. This software is more than adequate for most small to medium sized projects.
We now have the Fujitsu Design Simulator, which allows you to set up the whole system on a computer to check that everything works with everything else.
All aspects from selecting controls and optional parts to designing piping and wiring systems is made easier by the program’s built-in features.
Once the project is designed, the export functions can be used to output materials lists, product specifications, refrigerant calculations and more. It can also export to Word or Excel and group relevant CAD data for your project.
There are many load estimating software packages available. Some relatively simple free calculators can be found on the internet but any self-respecting contractor or designer should purchase something more sophisticated, such as AC Calc by Click Software, which uses industry recognised methods to model old and new building types. This software is more than adequate for most small to medium sized projects.
We now have the Fujitsu Design Simulator, which allows you to set up the whole system on a computer to check that everything works with everything else.
All aspects from selecting controls and optional parts to designing piping and wiring systems is made easier by the program’s built-in features.
Once the project is designed, the export functions can be used to output materials lists, product specifications, refrigerant calculations and more. It can also export to Word or Excel and group relevant CAD data for your project.
Ask a consulting engineer for help
Of course, the larger a project gets, the more complex it becomes, and for this reason it is usually wise to employ the services of a consulting engineer to do the calculations for you or on behalf of the client as part of the design process.
More sophisticated heat load calculations are necessary for larger buildings to meet new building regulations so the consulting engineer will liaise with manufacturers to produce a system design and specification that meets your client’s needs and current requirements.
www.fgeurofred.co.uk
More sophisticated heat load calculations are necessary for larger buildings to meet new building regulations so the consulting engineer will liaise with manufacturers to produce a system design and specification that meets your client’s needs and current requirements.
www.fgeurofred.co.uk
