Week 8 Water-source heat pump

Shallow water (groundwater, rivers, lakes, oceans, etc.) in the earth's surface absorbs the sun's radiation energy into the earth, and the temperature of the water is generally very stable. Water source heat pump system extracts heat from the water to the building to meet the needs of users of heating and cooling. Water source heat pump is a kind of clean renewable energy technology.

1.     High efficiency and energy saving 

Water source heat pump units use the water temperature of 12-22 degrees Celsius in winter, the water temperature is high than the ambient air temperature, so the heat pump cycle of the evaporation temperature is increased and the energy efficiency ratio is also increased. In summer, the water temperature is lower than the ambient air temperature and the efficiency of the unit is improved.

2.     Environmental benefits 

Water source heat pump use electric energy. Electric energy is a kind of clean energy, but in power generation process it consumes primary energy and lead to pollutants and carbon dioxide greenhouse gas emissions. Electricity consumption of water source heat pump units, compared with the air source heat pump, equivalent to more than 30% reduction, compared with electric heating, equivalent to less than 70%. Water source heat pump unit run without any pollution and can be built in a residential area. The system has no burning, no smoke, no need for stacking fuel waste sites and no long-range transport of heat. The transportation and storage cost of fossil fuel is saved, and the air pollution caused by the pollutant emission of the coal burning boiler is solved.

Reference List:

Wenku.baidu.com. (2011). Working principle of water source heat pump. [online] Available at: http://wenku.baidu.com/view/94b58d0202020740be1e9b9e.html?from=search [Accessed 30 Apr. 2016].

Week 8 The advantages of Ground-source heat pump

（Source: Google image, 2016）

Ground source heat pump system is an air-conditioning system which use geothermal resources of the earth's surface for warming and cooling. The main characteristics of ground source heat pump air conditioning system are as follows:

1.     High efficiency and energy saving, low operating cost   

Compared with the boiler heating system, 70% of the energy provided by ground source heat pump is sourced from the earth and 30% of the energy from the electrical energy. As a result, it will save more than 1/2 of the electric energy than the electric boiler, saving more than 2/3 of the energy than the foil boiler. As the heat (cold) source temperature of ground source heat pump is more stable, compared with the traditional air conditioning, its energy efficiency is higher than about 40-50%.

2.     Green environmental protection, less pollution

The ground absorbs nearly half of the solar energy our planet receives. As a result, the earth remains at a constant, moderate temperature just below its surface all year round. Ground source heat pump systems take advantage of the stable temperature underground using a piping system to exchange heat between your home and the earth, providing heating and hot water at remarkably high efficiency. There is no combustion, no smoke, no waste, no long-distance transport of heat, no gas emissions into the atmosphere in the heating and cooling process of ground source heat pump system. Therefore, it has environmental benefits significantly.

3.     Convenient and comfortable, reliable operation

Both temperature controller and remote controller can control the heat pump unit. Moreover, the indoor temperature can be adjusted in the set temperature range according to the need; Heat pump unit is small in volume and can be installed in indoor or outdoor. The system eliminates the need for a boiler room, cooling tower, an outdoor machine and other outdoor equipment. In addition, the system has no coal storage, tanks and other safety and health hazards.

Reference List:

Gns.cri.nz, (2015). Soil/Ground Conditions / Geothermal Heat Pumps / Using Earth Energy / Earth Energy / Science Topics / Learning / Home - GNS Science. [online] Accessed 26 Apr. 2016, <http://www.gns.cri.nz/Home/Learning/Science-Topics/Earth-Energy/Using-Earth-Energy/Geothermal-Heat-Pumps/Soil-Ground-Conditions>.

Liu, YY. (2015). Geothermal Energy To Become Next New Source of Chinese Renewable Growth. Renewable energy world .com.[online]. Accessed 26 Apr. 2016: <http://www.renewableenergyworld.com/articles/2014/07/geothermal-energy-to-become-next-new-source-of-china-renewable-growth.html >.

Week 7 Construction Waste

The construction industry produces a large amount of construction waste every year. According to statistics, China has a total construction area of more than 400 square meters in 2006, and the existing building area produced at least 2 billion tons of construction waste. The number of construction waste has accounted for 30% ~ 40% of the total municipal waste. Moreover, the pollution of construction waste is equivalent to two times of the automobile exhaust gas.

Construction waste is mostly solid waste including scattered mortar, concrete, scrap metal, bamboo, wood, waste decoration materials and a variety of packaging materials and other waste. Construction waste is a kind of resources that putting in the wrong place. The waste wood, which is removed from the building, can be used directly as a wood. The waste wood, sawdust and wood chips of the construction waste can be used as fuel, covering the compost and erosion in protective engineering. Waste wood can be used for the production of composite materials. Compared with ordinary concrete, it has the advantages of light weight, small thermal conductivity, so it can be used as insulation material. Broken bricks can be used to produce concrete blocks. After the concrete block is broken, it can be used in the production of recycled concrete, recycled cement, or as roadbed material. The production of cement with waste concrete as materials can save a lot of limestone, natural stones, iron resources and also be less coal combustion.

Reference List:

Ye, Y. and Zhang, D. (2015). Current situation and suggestions of construction waste disposal. [online] Wenku.baidu.com. Available at: http://wenku.baidu.com/view/a7df2c72bb68a98271fefa99.html?from=search [Accessed 23 Apr. 2016].