Enhancement of Cooling and Ventilation Functions of Buildings with Parts of Exterior Walls and Eaves

In this paper, a new solution for improving of cooling and ventilation function of some parts of exterior wall of buildings, like sunshades is provided with architectural passive design. In summer, Risen hot air is an important specification to enhance radiation heating, which the common passive solution for its removing is using chimney effect to conduct heat air to the out. Another way is using some windows or any kinds of under roof opening that can transfer risen hot air to out. Commonly, the old ways were associated with energy losing system. So they were in contrast with sustainable architecture and energy saving theories. In the other hand, in some regions, possibility of air leaking and removing hot air is minimum because of unfavorable prevailing winds and high relative humidity. So it is important to design a passive system which cools and ventilates the interior space without air leaking and energy losing. First step of designing this system is studying about North Arasbarans Specifications such as winds, vegetation and others, like cooling function with radiation-cooling and radiation-heating specification of different part of exterior walls especially eaves, sunshades and overhangs. In designed passive energy system, best application provided with converting solid volume of eaves from masonry to hollow one, located a central horizontal wall with a water pond on it, use the radiation specification of environment and make vegetation on it, while produce cooling and ventilation without any kind of active energies and made a passive cycle in sustainable buildings. In this research, first step is studying about some specifications such as winds and finding the unfavorable factors of them that effect on architectural design of buildings in North Arasbaran. Second step is making the green channels that can conduct the wind in suitable direction for cooling and ventilation uses. Direction of green channel should be in harmony with prevailing wind. Role of Angels of meshes of green channel is trapping the wind in green channel that plants on meshes enhance its potential. Deflection of angles of green channel increase the speed of wind in it and improve its efficiency. Rain water is used in designed system while two reciprocating pipes circulate water in system and send it back to source tank. Some drains on roof collect wasted waters and conduct them to the tank. Main parts of designed system are two ponds on sunshade that one of them is made of copper and another one from glass. Rain water conducts to glass pond and cool around of sunshade with passing wind. Copper pond radiates the cooling produced in glass pond to interior spaces with combining the physical and environmental capabilities and specifications of water, wind, plants and building parts and pipes while conduct the water to tank again. After designing the passive cooling system of sunshade, some tests is done to examine the efficiency of system partly. First test is about the effect of plants on cooling of buildings and led to selection of suitable plant species for using on green channel. Second test estimates the effect of wind on building in selected direction, 3th test insert the effect of evaporation of water in efficiency of designed system and last one review the impact of three factors on eacother and all of them on energy use of building. A house in Arasbaran is selected and some models were made. Models were created based on various stage of tests and the result of each stage was inserted to next model for another stage of test. Results of tests were analyzed and structural problems were removed from designed passive system. In general, it can be said that designed passive system is a conditioner which sunshade and any kind of active energies like AC power flaw or gas energy have not been used in it because of management of natural energy uses. It is very important to check the weather to find that the power of local winds can cool the water in glass pond or not while designed system needs to insulate against the climatic factors in some regions that have cold winter or hot summer but some regions like temperate climates do not need the thermal insulation all over the designed system. Plant on meshes of green channel is one kind of thermal and humidity insulation around the passive system. So it is better to study about the needs for insulation in different regions with various climatic factors. This research is based on “Research and Development” (R&D) which is done on the case study through analytical method. The results show economic performance and efficiency of designed system through tests, local experiences and observations in Arasbaran.