Problems developing High level Tool

The High Level Selection Tool displayed in our methodology is the group’s final Selection Tool. Previous to the development of this version there were other attempts made at developing a selection tool based on a various types of grading systems with the technologies listed at the side and performance criteria listed across the top. The intention of this type of selection tool was to enable unsuitable technologies to be ruled out quickly by referring to the tool to allow more time for in depth analysis of possible options. The under-development formats are shown in Figure 1.

Figure 1: High Level Selection Tool based on Grading System.

Making the table function as intended was a major problem, the problems associated will now be discussed in further depth.

As can be seen from the above table the technologies are graded N/A (Not Applicable), Good, Medium or Poor against each performance criteria.

The problems the group discovered with grading in this fashion are as follows:

· Gradings were based on developing personal knowledge of the technologies, for this reason they were open to subjectivity and debate from users of the table.

· Gradings were relative to other included technologies and when including such a large number of technologies the accuracy of an inflexible grading system was questionable.

· Applicability to technology, for example in the above table for Mechanical Supply and Extract Good Acoustics is graded as Medium. These Ventilation systems can in fact be designed to perform very well acoustically and produce little or no noise, therefore acoustics are not a function Mechanical Ventilation systems but a function of design; so in this section should have been marked N/A.

· Table was 2-Dimensional and did not accommodate for complexities, for example did not consider factors such as climate, site location and numerous others.

· Difficulty in understanding what gradings were supposed to represent in some cases, for example CHP in the Low Embodied Energy column is graded Poor, this is supposed to represent a large amount of embodied energy in the use of CHP, it is not easy to make the mental connection quickly and this makes hard work of understanding the Selection Tool defeating the intended purpose.

In an attempt to incorporate greater flexibility and clarity into the Tool other grading systems were developed for example, as can be seen from the Tool for Cross Flow Natural Ventilation, the Good Thermal comfort performance criteria is graded M,P; what this stands for is medium Positive and this is intended to represent a medium good (Positive) effect on Cross-Flow Ventilation as opposed to M,N (medium bad). In increasing flexibility this tool succeeded to a degree but the problems of subjectivity, relativity (although slightly diminished), applicability, complexity and difficulties in understanding the grading system still persisted.

The Solution

The group came to agreement that to develop a High Level Selection Tool on a grading system basis was very difficult, if not impossible to achieve, certainly in the given timescale of the project of 12 weeks, following brainstorming sessions the group consensus was to develop a reference type High Level Selection Tool.