Hyperthermia is becoming a bigger problem with higher temperatures. It has gotten more attention in the news for the upcoming Olympic Games in Tokyo, and for big marathons where this is becoming an increasing problem. Whereas, able-bodied persons are able to dissipate heat by means of sweating, a tetraplegic most likely cannot. When the lesion is above T6 there is a possibility of having a dysregulated thermoregulatory system. This means that the temperature signals are not received, and therefore no reaction will occur due to a rising core temperature. The fact that they cannot control their own body temperature gives them a high risk of hyperthermia. Research was conducted concerning the problem. The solutions currently used are wet towels, water beads, water spray, and cooling products such as evaporation and phase change material (PCM) vests. The downside for these products is their limited duration. Products based on evaporation need to be refilled after several hours, depending on the temperature. PCM packs need to be restarted at a cool place, such as a fridge or freezer. There is currently one active cooling product which cools the wheelchair user's back by means of air. The research showed that the users have a big need for an active cooling product, which could keep them cool for an entire day. Due to the lack of sweating for tetraplegics, it has been decided to implement air and liquid cooling. For tetraplegics the area in which the most heat is found is the upper chest and back, which are the areas with the highest sweat rate for able-bodied as well. The design goal of the project is to develop an active cooling system to prevent hyperthermia while outside, which can also be used by tetraplegics during their everyday lives. The goal is achieved when the user has a reduced increase of core temperature during their day outside. VENTS is a shirt that helps the user stay cool during warm days. VENTS has four fans, two on the front and two on the back, which will create an airflow and improve convection. There is a temperature sensor included to make it a fully automated cooling product. If the fans are not enough to slow down the temperature increase within the body, the water pump will start distributing water droplets across the torso of the user. This is done by having tubing at the collar of the shirt, with outlets to create the small droplets. This process will re-enact sweating as well as help with convection and evaporation heat loss. If the product works on full cooling power it can extract about 28 Watts worth of heat from the body. With the help of the Fiale model and the user testing data, a simulation was conducted with VENTS in an environment of 35°C and 80% humidity, along with an activity level of 4 metabolic equivalent of task (MET). This simulation shows a 3.94°C decrease of skin temperature compared to not using the product.