Autonomous Garment With Active Thermal Control And Powered By Solar Cells

Abstract

The invention refers to an autonomous system and to a method that allows the active thermal control of garments using solar cells as the power source. In the simplest configuration, the system includes a piece of clothing with solar cells (1), a thermal module able to generate heat and cold (3, 4, and 5), and a unit for controlling and monitoring the internal environment (6). In order to increase versatility and to optimize operation conditions, the system includes batteries (2) that can be charged by the solar cells or externally, increasing energy autonomy and improving performance in low radiation conditions. Proper distribution of electric resistors (3) and refrigeration pipes (7) allow a fine-tuning regulation of temperature inside the garment. The garment is developed not only for standard conditions but also for extreme heast and cold environments, being optimised wither for standard solar radiation or other relevant spectral source.

Description

RELATED DOCUMENTS [0001] There are many patents related with this invention. Some documents are associated with heating techniques in garments: WO03059099, EP1197722, US2001047992, DE19835984, U.S. Pat. No. 5,893,991, U.S. Pat. No. 5,643,480, EP0287294, U.S. Pat. No. 4,705,935, FR2577390, US2003006229, and U.S. Pat. No. 4,404,460 that use the thermoelectric effect; FR2752363 mentioning solid and liquid fuels; U.S. Pat. No. 6,439,942 and FR2577116 describing solar arrays; U.S. Pat. No. 4,539,714 utilizes microdendritic solar energy collectors. Other documents are related with cooling procedures in garments: DE19755181 and DE19749436 describe flexible stripes; GB2352385, U.S. Pat. No. 6,125,645, U.S. Pat. No. 5,289,695, and U.S. Pat. No. 5,111,668 include appropriate materials; WO02067707, U.S. Pat. No. 6,257,011, FR2719892, and U.S. Pat. No. 5,217,408 mention forced ventilation by fans; U.S. Pat. No. 5,438,707 uses fans and compressed air; U.S. Pat. No. 6,134,714, US2002073481, US200...

AI Technical Summary

Benefits of technology

[0024] The present invention reduces limitations both in portability and autonomy, and allows warming and cooling thermal cycles in the same piece of clothing. One of the main goals of this invention is to solve these limitations without a significant increase in weight. Furthermore, it foresees a more efficient way to manage temperature distribution and power resources.

[0027] The utilization of batteries in the garment is convenient not only to store energy but also to provide power stabilization, namely when power transients occur in the solar cells. New technologies allow the development of ultra-thin flexible batteries, and their series and parallel association increase the power storage to more that 200 Wh / kg. Moreover, thin batteries are easily shaped so that weight distribution in the garment is possible and substrate flexibility allows ergonomic profiles.

[0028] The devices utilized to produce cooling use different techniques. Peltier cells are made from two dissimilar metals and the application of a DC voltage to a closed circuit gives rise to a temperature change at the junction of the two metals. Peltier cells do not have moving parts, are lightweight, and can be used in any orientation. Furthermore, they may be stacked to achieve greater temperature differential. Miniaturized compressed cooling machines with coefficient of performance (COP) ˜4 are available. Thus, vapor compression cycles are very efficient systems providing a cooling process to garments. Additionally, the utilization of thin flexible pipes allows a proper distribution of thermal flow across the piece of clothing.

[0029] The most effective method to provide heat to the garment is the conversion of electrical energy in heat by means of resistors. Wiring, high flexibility, and weightless of electrical resistors make them the more suitable elements to generate heat inside the garment.

[0031] Wiring is an important issue for assembling procedures. Although solar cells, batteries, resistors, and pipes have high flexibility it is fundamental to study stress and fatigue in some of the junctions of the garment, namely those related with the human articulations.

Problems solved by technology

Most autonomous systems available on the market generate either heat or cold, and do not have both solutions embedded in the same garment.

Thus, systems connected to power lines are neither portable nor autonomous, and solutions with batteries have low autonomy.

Therefore, autonomous pieces of clothing need large and heavy batteries or must utilize very low power, preventing the addition of thermal control units, mainly cooling solutions, where the thermal cycle efficiency is lower.

Images