As technology advances humans have tended to increase exploration in environments that are thermally unsafe. To survive in these environments knowledge of human thermoregulation system (HTRS) is critical to aid in the development of proper clothing and protective suits. Our approach is to obtain this knowledge through mathematical modeling. Thru the time different researchers have study the HTRS and developed different models to explain it.

Those models could be grouped in two different mayor approaches; the analytical and the empirical. Although the analytical approach can give us a result with accuracy following the laws of physics, it does not include the effects of some functions of the human body such as adaptation and acclimatization. The complexity and the lack of knowledge of the physiological behavior of the human body limit the theoretical approach. With the empirical approach the problem is that the genetic variation in humans makes almost impossible a reliable empirical model of HTRS. Moreover, it is very difficult to obtain data for the HTRS and, a trustworthy empirical model will require an enormous amount of data. Obtaining all the data needed for such a model will be time consuming and very complex to achieve in reality.

There is a need to develop an accurate model which requires only a small amount of data. A semi-empirical model developed by Hulting (2002) seems to be a promising answer to solve this problem. Hulting presents a semi-empirical model called the semi-empirical technique (SET) which uses phenomenological model forms and an understanding of the process in order to reduce the amount of data required in modeling the process. Her model utilizes the human body as a device which performs different processes, permitting this way that the HTRS can be modeled as a multiple input, multiple output (MIMO) process. Also, Hulting showed in her work that the SET approach benefits of the statistical design of experiment (SDOE). The SET model developed by Hulting is the only semi-empirical model, which the author is aware of, that address the interaction effects of HTRS as a multiple input, multiple output (MIMO) processes.

Hulting successfully showed that this approach can model the human thermoregulatory responses with an acceptable accuracy. Although her work seems to be accurate, the model was based on simulated data, so it can not be considered suitable until some actual human are modeled. On 2005 Rollins et. al. extended this approach and attempted to validate this model using data obtained from studies of Stolwijk and Hardy (1966).

Although they modeled acceptably the data, but their model can not be completely validated because the data that Stolwijk reported was an average for three subjects HTRS responses and not the response of a sole individual. At this moment the author have not found any reported data that fits our validation purpose. That is why it is intended in this research to validate the SET model by conducting experiments with actual humans and modeling their responses using the SET model. Our results will finally validate the model developed by Hulting and demonstrate once and for all that this approach has the capability to model the HTRS. As a result this model can be used in the design of environment control systems such as astronauts' thermal suits and protective clothing.