(译稿)新农村建设生态型住宅可再生能源利用技术.doc

The Technology of Applying Renewable Energy in the New Countryside Ecotype Houses
Abstract: Due to lack of scientific design and appropriate technology guidance, countryside houses in our country are universally in poor thermal environment, lag behind in energy production and application, and obvious on energy waste, while the energy consumption on countryside houses is increasing. We should on one hand advocate energy saving, and on the other hand search for renewable energy like solar energy, geothermal energy, wind energy and biologic energy. This article gives analysis on applying solar energy and biogas energy technologies and puts forward some economical and appropriate technological measures about renewable energy application as technology support and theory guidance for constructing new countryside ecotype houses.
Key words: New countryside construction; ecotype houses; solar energy; biogas energy
1 Introduction
As the continuous development of countryside economy, it has been country people’s urgent necessary to improve houses functions and living environment, and constructing economical and beautiful green energy-saving houses. The fact is due to lacking of scientific design and appropriate technology guidance, the countryside houses in our country have been in irregular and disorder state for a long time, and the most-seen is the traditional extensive model. In recently year, there’s an obvious trend of increasing energy consumption in new countryside houses construction. It has become an unavoidable strategic topic for new countryside construction to construct a safe, healthy and comfortable countryside houses environment while no obvious energy consumption noted.
Tsinghua University Construction Energy Saving Research Center used to launch a big and comprehensive investigation and research on countryside construction, energy and environment. The result shows that the countryside people’s income is increasing continuously and they’re able to purchase certain commercial energy on one hand, while on the other hand the energy consumption of countryside houses is increasing constantly. As the faster development of countryside economy, ecotype new countryside construction has caught more people’s attention.
Energy has been important material basis for human existence and development. To deal with the possible energy and resource shortage problem, we should actively advocate energy saving and search for renewable energies like solar energy, geothermal energy, wind energy and biologic energy. This article gives analysis on applying solar energy and biogas energy technologies and puts forward some economical and appropriate technological measures about renewable energy application as technology support and theory guidance for constructing new countryside ecotype houses.
2 Solar energy application technology
Solar energy is a kind of inexhaustible renewable energy, substantial and renewable. Most parts of our country are rich in solar energy, and it has good exploitation conditions and great utility value. The application of solar energy on construction include space heating, lowering temperature, water heating and so on, which can be divided to two categories of active and passive.
Active solar houses are force circulation solar energy collection systems that consist of solar heat collector, radiator, pipeline, blower or pump, and heat storage equipments. The active solar houses require high investment, complicated technologies, frequent maintenance and certain regular energy consumption. However, passive solar houses don’t need or only a little motive power, equipment, or equipment maintenance. The passive solar houses take use of the solar energy for space heating and energy saving. They have good economic, social and environmental benefits. As a result, it’s more appropriate to use passive solar houses for countryside houses.
2.1 The structure design of solar houses
To make use of solar energy from flat design angle, we can apply a model of extra sunlight rooms or sunlight corridors in the countryside houses. The sunlight rooms are south-oriented, and we can use south-oriented corridors, sealed-up corridors, vestibule, etc. The south side should be transparent glass walls, the roof be strength-enough(for human safety) slope glass to maximize the heat storage capacity. The extra sunlight room should be floored with high coefficient of thermal storage materials like cobbles, to collect more heat. Meanwhile double-layer glass should be applied to minimize the heat loss at nights, roller blinds also applicable. At the same time, there should be a 1m2 air outlet for every 20～30m2 glass wall of the sunlight room to guarantee good ventilation and prevent the room from getting too hot in summer.
2.2 Analysis on sunlight rooms’ energy efficiency benefits
Graph 1 is one countryside house with extra sunlight room. On December 2010, we tested the temperatures of the sunlight room, ordinary room(living room), and outdoor. The testing time is December 21-25, 2010. During the testing, the heating is off. The test equipment type is JT-II temperature and heat flow inspection instrument and thermocouple. The result shows as follow:
Food storage room
kitchen
Fiery pit

Central room
Sunlight room
bedroom
Living room
bedroom

graph1 countryside house with extra sunlight room

Outdoor temperature
Ordinary room temperature
Sunlight room temperature
time

graph2 the comparison of temperatures of sunlight room,ordinary room and outdoor

The result shows that the average temperature of the sunlight room is 13.5℃ higher than that of the outdoor temperature, and the highest temperature difference reaches as high as 18.4℃, while the lowest is 7.2℃. It shows that building sunlight room on the construction’s flat structure is helpful to raise the room temperature, make for room more comfortable and lower the energy consumption for space heating.
2.3 The section position of the sunlight room
Most new countryside houses appear as 2 or 3 floors, and the sealed-up corridor, which is used as sunlight room, is usually set on the second or third floor. Which floor should we choose to better improve indoor heat environment and lower construction energy consumption? Will the overhanging sealed-up corridor shelter the underneath room from solar radiation?
To state this impact, we take Zhang Jia Kou as an example to figure out the biggest sun visor necessary on Winter Solstice and Great Cold days. For Zhang Jia Kou’s south-oriented houses with window height of 1.5 m, the biggest sun visor on Winter Solstice day is 3.1m, while 2.69m on the Great Cold day. The hanging out length of corridor in most south-oriented houses is no more than 1.8m, which suggests that on Winter Solstice and Great Cold days the sealed-up corridors on the second or third floor will not shelter the underneath rooms from solar radiation. That’s to say, we can set the sunlight room on either floor while considering elevation molding and people’s living habit.
3 The application technology of biogas energy
Biogas is a kind of combustible gas that yielded through microbial fermentation from organic substance under anaerobic environment condition with appropriate temperature, humidity and PH value. Biogas is a good and clean fuel, and all excrement of animals with agricultural products waste and life organic waste can be used as its raw material for fermentation. And temperature is an important external condition for the fermentation.
In the countryside, the fermentation relies on natural temperature. So the higher the temperature is, the more gas will be yielded. To guarantee good yield of biogas in winter, we need some technologies to raise the biogas generating pits’ temperature and improve the gas yielding efficiency.
3.1 Technologies for improving biogas yielding
3.1.1 Take full use of the afterheat of green feed storage pool
In present countryside, the cultivation of domestic animals has shifted from free vacation to confine model. Farmers have to store a lot of green feed as the animals’ feed for the whole year. Farmers begin the storage on August and will last for one year. The green feed storage pool are usually 2-5m under the earth. We tested a green feed pool of north Meng Niu base on December 2009. The pool is 2.5m under the earth and reaches 2m above the earth. The green feed temperature under the earth level is 23℃ and relatively stable. But we theoretically figure out that the highest temperature at the place of 2m under the earth of Zhang Bei area is only 29.6℃, while the lowest is -12.0℃. So we get that the temperature of green feed storage pool is far higher than that of under-earth temperature at the same level. So we suggest combine the construction of biogas generating pits with green feed pools and take the all round of the biogas pits as storage space of green feed to raise the biogas pits’ temperature to increase the heat amount and gas yield as a result, so that the biogas generating pits yield gas regularly even in winter.
3.1.2 Apply solar greenhouses to raise biogas pits’ temperature
Solar greenhouses are built according to glass’ greenhouse effect theory. The shortwave radiation of sunlight can go into indoor space via passing through glass or other transparent materials, while glass functions as opaque subject to long-wave radiation. In such way, we can constantly raise the greenhouses’ air temperature and floor temperature.
The result shows that the indoor average temperature of solar greenhouses is 13.5℃ than that of the outdoor, the highest difference is 13.5℃ and the lowest is 7.2℃. If we build solar greenhouse great pavilion, the temperature difference of indoor and outdoor will be higher and can reach as high as 30℃. If we build solar greenhouses above the biogas pits and combine them, we can raise the earth temperature and increase the heat amount of biogas pit in a remarkable extent. Considering to lower the cost on new countryside construction, we can apply plastic membrane great pavilions instead of glass above the biogas pits. To increase the heat amount of the biogas pit and considering the high air temperature in the greenhouse, we should try to increase the earth temperature in the greenhouse and so we pave high coefficient of heat accumulation pebbles on the earth surface of the greenhouse. To reduce the heat loss at night, we should enhance heat preservation of the east-oriented, west-oriented and north-oriented walls with roller blinds set above the glass or semitransparent-equipped top.
3.2 “Combine five to one” biogas energy comprehensive application technology
The “combine five to one” plan is base on drylot feeding stock farming model, take biogas engineer construction as a link to combine family-based farming production and life, energy exploration and ecological construction. The method is combining the construction of stock-raising house, biogas pits, living houses and green feed pools via biological mass-energy conversion technology By comprehensive optimization design, we’re able to get a good recycle of reusing ecosystem energy and substance in many levels to mutual promote between stock breeding and biogas yield, and a good recycle of substance circle and energy circle. This combination is to promote the development of farming industry and convenient farmers’lives.
The ”combine five to one” plan include following basic factors: a appropriate scale stock raising house, a under-earth free feed storage pool, a 10M3 biogas pit, a solar greenhouse, a farmer living house and a toilet. The biogas pit should be under the earth of stocking raising house to convenient cleaning and raw material putting-in; On the other hand , take use of the all-round space of the stock raising house as green feed storage pool for keeping the under-earth’s temperature and guarantee the biogas pit reaches gas-yielding requirements. The living house should be near to the stock raising house and biogas pit to convenient management of farming production and biogas engineer. We can also link the toilet with the biogas pit to convenient toilet cleaning and raw material putting into the biogas pit. Take the fact that the raw material into biogas pit are usually excrement and urine of cow, sheep and horse and such kind of things are easy to get crust into account, we can use the rich wind resource in the plateau area as driving force to stir the biogas pit continuously. In such way, we can avoid the crust problem and enables enough contact of the raw material and bacteria, and raises the biogas pit liquid’s temperature to improve gas-yielding efficiency. We can build solar greenhouse on the other hand to further raise the temperature.
The plan applies ecological design theory to make full use of clean and recyclable resource while aiming at minimizing emission during substance recycling, to maximize the appropriate usage of resource. The design goes as shown in graph 3, and the detailed plan sketch shown as graph 4 and 5:

Graph 3 the over view of the design process

Graph 5 “flat design (II)
1-bedroom；2-kitchen；3-living room；4-extra sunlight room；5-biogas pipeline；6-corridor；7-human excrement entrance；8-toilet；9-stock excrement entrance；10-raising house；11-overflow gutter；12-fence；13-solar greenhouse；14-outlet port；15-windmill；16-biogas pit；17-green feed storage house.
Graph 4 flat design(I)
1-bedroom；2-kitchen；3-living room；4-extra sunlight room；
5-biogas pipeline；6-raw material storage pool；7-solar energy raising house；
8-raw material entrance；9-biogas pit；10-windmill；
11-toilet；12-human excrement entrance；13-biogas pit exit；
14- hydraulic room；15-flow through；16-stock house exit；17-green feed storage pool.

4 Conclusion
As stated above, In the process of new countryside houses construction we have the following conclusions about the renewable energy application technologies:
(1) Passive solar energy model is applied to design flat new countryside house, and the appropriate form is extra sunlight room or sunlight corridor. The sunlight room is usually south-oriented, and it can be set on the second or third floor without shelter the underneath rooms from solar radiation. In the flat design we add sunlight room and corridor to raise room temperature, make more comfortable indoor, lower energy consumption and save energy.
(2) Low temperature has been the key factor to limit the yield of biogas. By applying the “combine five to one” comprehensive ecological technology by combing biogas pit, green feed storage pool, solar greenhouse, stock raising house and toilet, we are able to make full use of the relative high temperatures of the green feed storage pool and solar greenhouse, to guarantee the good yield of biogas in cold winter.
References (参考文献)
[1] Y. Li and Y.Z. Wang:Architecture Technology, vol.40 (2009) No.1, p. 38-41.
[2] JiaPing.