Qualitative Experiments
The qualitative experiments were used in order to determine the human response to the PV system. This experiment involved running the system at set parameters and asking participants various questions, using a quastionnaire, about their thermal comfort. Six different conditions were tested, for ten minutes each, on ten participants. The overall test procedure and conditions tested can be seen below in the table provided and the system set up in the same manor as discussed for the quantatitive experiments shown here. It is also important to mention that ethical approval was sought from the Departmental Ethical Committee to carry out the test, which was granted on the 15th January 2014.
Participants
Subjects were selected randomly, and asked to read a detailed information sheet and sign a consent form before participating which can downloaded from the link provided. There were five males and five females, and all were in good health. Throughout the experiment they were allowed to continue with their own work as normal and the metabolic rate was approximately 1.2Met. Before the experiment started the subjects adjusted their own clothes to feel neutral at the room temperature. All subject's clothing insulation rate were around 1clo.
Questionnaire
The participants were asked to complete the questionnaire at the end of each condition, giving six responses in total. This was to give their body time to adapt to the new thermal conditions. The questionnaire was divided into five sections: thermal sensation, air movement, irritation, discomfort, and a final overall comfort level. The full questionnaire can be downloaded by clicking on the link provided.
1. Thermal sensation
The first question is about thermal sensation level. This used the ASHRAE thermal sensation scale, known as PMV (Predicted Mean Vote), a scale divided into seven thermal conditions from cold to hot. In addition to the scale, one further question was set to understand which temperature was currently preferred by the participant - it is possible for them to feel “warm” without desiring a cooler temperature.
2. Air movement
The second question relates to air movement acceptably - this is an important factor for human comfort levels. A neutral vote was not allowed in this section, thus the scale has two parts. Similarly to the first question, there is a follow up question to determine the preferred air movement level.
3. Irritation
The third question considers irritation level. It shows whether the subjects can concentrate on their own work or not.
4. Uncomfortable part of the body
The fourth question is to determine whether any localized discomfort is felt in sensitive regions (e.g. eyes), these factors have been found to be important in determining comfort.
5. Overall comfort level
The final question is overall comfort level; all of the factors above (and any others) are to be considered and included in this question.