作者：[德]施維德 博士 (斯圖加特大學、設能建筑咨詢（上海）有限公司)

Author: Dr. Dirk Schwede (Stuttgart University, energydesign (Shanghai) Co., Ltd.)

Email: dirk.schwede@energydesign-asia.com

來源：可持續建筑能力中心

下文節選自2017年econet monitor綠色建筑特刊，第26-27頁。

The following text is excerpted from the Econet Monitor Special 2017, page 26-27.

相對于德國的單一氣候，中國的一些地區更容易達到用能需求和光伏產能之間的平衡。因此，我們對中國26個城市（圖1）進行了研究，以確定各地的具體能源需求以及屋頂光伏建筑一體化系統潛在的產能量。根據各地的能源需求特征，我們對不同氣候區域的建筑節能改造策略進行了深化。基于德國家庭目前的生活標準我們計算出了這26個城市的家庭能源需求量。研究中設定中國家庭配備的家用電器和德國相似，并且所有家電都是中國市場上可購買到的最高能效等級（等級一）。

While Germany’s climate is rather uniform, there are places in China where the energy demand and the energy production from a PV system is easier to be balanced than in other places. Therefore, an investigation of 26 locations in China (fig.1) has been conducted in order to determine specific energy demand profiles at the sites and the potential output of roof-integrated PV systems. Based on energy demand profiles, strategies adapted to different climate zones for energy saving have been developed. The energy demand for a modern lifestyle has been calculated, based on current household demand in Germany. It has been assumed that households in China are equipped with appliances similar to Germany and that all appliances are of the highest Chinese energy-efficiency class (level1).　

圖1 研究中涉及的中國不同熱工氣候分區下的26個城市

fig.1 26 locations in all building climate zones in China for the investigation

每個城市南向光伏板在不同傾角下的系統輸出都得到了計算（圖2）。結果顯示光伏系統在大部分城市的產出均比德國斯圖加特高。這歸因于更長的日照時間和更高的太陽高度角（緯度更低并且更穩定的太陽路徑）。其中光伏系統在拉薩的產出最多，因為拉薩海拔高，天空能見度高并且晴朗。廣州光伏系統的產出最少，其原因歸咎于較高的空氣濕度和普遍的云層覆蓋造成的大量漫反射。總體上來說，相較于制冷與除濕為主要需求的氣候區域，光伏系統更適合于以供暖為主要需求的氣候區域。此外，就研究中涉及的所有城市而言，太陽能光伏板朝南并且有15度傾斜角時能夠獲得最大的系統產出。

The output of the PV systems has been calculated for each location for various system slopes for south orientation (fig.2). In most locations a higher output can be realized than in Stuttgart, Germany. This is due to longer daylight hours with higher solar inclination (a steadier sun path at low latitudes). The highest solar output can be achieved in Lhasa due to high altitude and its clear and sunny climate. Lowest PV output is achieved in Guangzhou, where the major part of the radiation is diffuse due to high humidity levels in the air and the prevailing cloud cover. In summary, heating climates are more suitable for PV power generation than climates with cooling and dehumidification demand. For all locations, a PV system with 15°-slope towards the south performs best.

圖2 中國26個城市不同傾角的屋頂光伏建筑一體化系統的太陽能系統輸出

fig.2 Solar systems output of a roof integrated PV system with various roof slopes in 26 locations in China

另外，研究中不同地區采用了不同的建筑節能改造方法，比如北方需要增加保溫層厚度，并使用三層玻璃，而南方則采用厚度適中的保溫層，并使用雙層防曬玻璃。而針對所有地區，建筑均被設定為圍護結構具有較高的氣密性，在使用空調的情況下采用機械通風，在過渡季節舒適的氣候條件下通過窗戶的開啟自然通風。在中國北部和西部地區，建筑的通風系統配備熱回收功能，在南部和東部地區，通風系統則配備熱和濕回收功能。供暖與制冷均采用最高能效級別的分散式系統。

On the other hand, the energy saving concepts are characteristic for the specific location with, for example, increased insulation thickness and 3-pane glazing in the North and moderate insulation thickness and 2-pane sun protection glazing in the South. In all climates building concepts include an airtight building envelope and a mechanical ventilation system for times of conditioning demand and natural ventilation through operable windows in time with moderate outdoor conditions. Ventilation systems are equipped with heat recovery functions in the North andin the West, and heat and moisture recovery in the South and the East. Heating and cooling is generated with decentralized systems of the highest efficiency class.

我們對能源消耗（供暖、制冷、照明、熱水、輔助用能和家用電器）所對應的二氧化碳減排量和光伏系統輸出對應的二氧化碳減排量進行了分析（圖3）。結果顯示在所有氣候條件下三層樓建筑能實現碳中和，而六層樓建筑二氧化碳能夠實現50%的減排。在不考慮家用電器帶來的能源需求的情況下，六層樓建筑也能實現年度碳中和。

The energy figures are evaluated with CO₂ emissions for the local energy mix (fig.3). Balancing the CO₂ emissions from energy consumption (heating, cooling, lighting, hot water, auxiliary energy and appliances) and the CO₂ benefits from PV output, in all climates 3-storey buildings can be carbon-neutral and in 6-storey buildings the CO₂ emissions can be off-set by 50%. If the energy demand for appliances is not included 6-storey buildings can be carbon-neutral in their annual balance.

圖3（節能改造后）一層、三層和六層建筑能源消耗對應的二氧化碳排放量和采用光伏建筑一體化系統獲得的二氧化碳信用額

fig.3 CO₂ emissions and CO₂ credits for buildings with one, three, and six levels (after energy retrofit)

研究表明光伏建筑一體化可以在中國所有地區以及相關氣候條件下對既有建筑的低碳改造起到重要作用。就中國典型的舊城區五到七層的住宅建筑而言，必要的節能改造結合屋頂光伏建筑一體化系統能夠使既有建筑達到接近碳中和的標準（建筑本身不需要額外的能源供給）。

This investigation shows that BIPV can contribute significantly to a low carbon building stock in all parts of China and under all relevant climatic conditions. Considering typical residential apartment compounds with 5-7 storeys, the necessary energy upgrade combined with PV applications on the roof could result in a nearly carbon neutral building stock (building energy demand without energy use).

研究證明中國多層住宅在節能改造后的能源需求和能源產出可以達到平衡，下一步還需要政策的支持，充分面向未來的投資，優秀的工程設計和建造工藝，這樣中國城市低碳建筑的潛力才能夠真正實現。

As it has been shown that the energy demand and the energy generation can be balanced, a supportive political framework, sufficient future-oriented investment, good engineering and craftsmanship is needed to realise these potentials for low-carbon-buildings in China’s cities.