Control of passive solar system.

Without control high solar fractions arc difficult to obtain from Trombe walls, direct solar gains, and rock bins. Integration of all these techniques by control is absolutely necessary. A short review is given of the available sensors, actuators, and control systems. The control of individual solar techniques as well as several combinations are discussed; for instance, the control strategy for the combination of direct solar gains and Trombe Wall. Based on literature general conclusions are given about the energy efficiency of these systems in relation with the control strategy. A more detailed analysis is made of a costeffective simple passive solar system with adjustable window devices such as insulating rolling shutters, shading devices and vent windows. The benefits of modem control such as predictive control are compared with respect to simple and straightforward control strategies. Emphasis is put on the application of controlled ventilation for the maintenance of comfort in summer. Natural ventilation is strongly recommended here because of its passive character. In this paper special attention is given to the various digital control systems designed in a concerted action of the project PASTOR of the commission of the European Communities.