The criteria matrix was created to guide the user into selecting an appropriate HVAC system based on parametric inputs. Owners are asked first select the main parameters of Location and Size. After selecting these parameters the ratings for each system on a basis of the criteria (discussed here) are called to the matrix using the CHOOSE() function. Next the Owners are asked to rate each criteria group with a limited number of weighting points. Once all of the weighting factors have been applied appropriately the Criteria Matrix Selected system is displayed.
The functionality of the matrix is achieved through a series of IF() and CHOOSE() functions. Additional functionality was achieved through the use of SUM () and SUMPRODUCT() functions. The IF() functions are used to create a series of enhanced features on the Owner Selection Sheet. The criteria matrix functionality is achieved through the use of CHOOSE() function. A series of 15 possible parameters were created based the permutations of building location (5) and building size (3). The criteria was then inputted for each cell with a CHOOSE () function of 15 inputs, each input corresponding to a specific location and size combination. Each system is evaluated based on the criteria along the left side of the page with respect to the specific location and size combination. Then each output is multiplied by the criteria weighting factor selected by the engineer and summed using the SUMPRODUCT () function. The process is repeated for any criteria weighting that the owner selects and the value of the engineer's weighted values and the owner's weighted value are added with the owner's rating being given a weighting of 40% and the engineer's rating being given a 60% weight.
The system with the highest rating is then selected as the winning system. Below is a screenshot of the Owner's Input Page (Figure 1) and a screenshot of the inner workings of the matrix (Figure 2). Assumptions and Limitations of the system are discussed below. The excel file is linked below for your use.
The functionality of the matrix is achieved through a series of IF() and CHOOSE() functions. Additional functionality was achieved through the use of SUM () and SUMPRODUCT() functions. The IF() functions are used to create a series of enhanced features on the Owner Selection Sheet. The criteria matrix functionality is achieved through the use of CHOOSE() function. A series of 15 possible parameters were created based the permutations of building location (5) and building size (3). The criteria was then inputted for each cell with a CHOOSE () function of 15 inputs, each input corresponding to a specific location and size combination. Each system is evaluated based on the criteria along the left side of the page with respect to the specific location and size combination. Then each output is multiplied by the criteria weighting factor selected by the engineer and summed using the SUMPRODUCT () function. The process is repeated for any criteria weighting that the owner selects and the value of the engineer's weighted values and the owner's weighted value are added with the owner's rating being given a weighting of 40% and the engineer's rating being given a 60% weight.
The system with the highest rating is then selected as the winning system. Below is a screenshot of the Owner's Input Page (Figure 1) and a screenshot of the inner workings of the matrix (Figure 2). Assumptions and Limitations of the system are discussed below. The excel file is linked below for your use.
Some limitations of the criteria matrix are that it is difficult to evaluate a structure that is as simplistic as a emergency deploy-able structure. Some assumptions that were made to more easily define the possibilities of the system are:
- the structure is one story
- the structure is to be used <1 month to 3 months
- the structure is for residential use or non-medical occupational uses
- (ie. nothing requiring a pressurized system such as a temporary morgue, or medical facility)
Because of the temporary nature of this structure and the assumptions that assembly needed to be quick, and transportable, selection of HVAC system was difficult. Based on our criteria matrix we provided only two systems that were both able to heat and cool, VAV and CAV. The remaining systems only had one primary function. The result of which is that you will need to have a combo of the systems selected. In order to do this we would need to add advanced functions for this to occur automatically, which due to our limited time and experience were not completed. Instead to choose a combination, you would select the heating as the full value to determine which heating system would work best and then run the system with cooling being your main function.
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