2. Target recognition
2.1. Results of national special inspection on building energy efficiency
In 2005, the Ministry of Housing and Urban-Rural Development of China (MOHURD) carried out a special national inspection of building energy efficiency. The three main problems found regarding heating energy consumption in the northern heating region were heavy energy consumption, high heating costs and excessive financial subsidies to heating supply enterprises. These problems can be attributed primarily to the lack of metering and temperature regulation equipment to distribute heat load while still providing an affordable heating system. The present arrangement determines costs by heating area, rather than by heating load, and thus does not respond to a market economy and encourage energy efficiency. Even so, most heating enterprises derive little benefit from this system. Instead of reducing costs by actively saving energy, they are dependent on government subsidies.
2.2. Actual energy consumption results of 2×106 m2 residential building in Beijing
In 2005, the Chinese Academy of Building Research (CABR) tested the heating energy consumption and heat metering of 2×106 m2 of residential building area in 18 residential districts. Half of the buildings tested were designed to a 50% energy efficiency design standard (heating energy consumption=12.4 kgce/m2 a), and the other half to a 30% standard (heating energy consumption=17.4 kgce/m2 a). Results from the 50% design standard buildings showed an average heating energy consumption of 15.89 kgce/m2 a, equivalent to a 30% energy efficiency design standard, and the 30% design standard buildings showed an average heating energy consumption of 23.39 kgce/m2 a, equivalent to an energy-inefficient design standard (heating energy consumption=25.2 kgce/m2 a). This substandard performance can be attributed to two factors. First, construction did not adhere to an energy efficient design standard. And second, no temperature regulation mechanisms were installed, resulting in uneven heating with some residents having to open windows to eliminate excess heat. In one residential district the heat lost through open windows measured 25.8% of the total heat supply. This sort of energy waste is universal in China.
2.3. A successful demonstration project of EERFERB in Tangshan
Three residential buildings in “Hebei No.1”, a residential district built in 1978 as one of the first after the earthquake in Tangshan, were selected as a demonstration project of EERFERB. In winter, the maximum indoor temperature in these three buildings was 16 °C. The heat bridge from exterior walls was obvious, with condensation and mildew appearing on some interior walls. The fly ash roof insulation was compromised by excessive moisture. Most of the steel windows were deformed and could not be shut tight. No heat insulation measurements were ever taken in the heating supply system, and no heat metering equipment was installed. The retrofit addressed three areas: insulation of the building envelope, including exterior walls, roof, doors and windows, staircase partition walls and the head plate of the basement; insulation of to the heating supply system; and heat metering. After the retrofit, tests of the indoor temperature and metering of heat supply showed a decrease in heating energy consumption of 30%, with an average indoor temperature in excess of 20 °C. In one residential home test, with all temperature regulation valves shut, the indoor temperature held at approximately 20 °C every day