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It is a question if large scale heating/cooling network could be applied in China economically, environmental protection and energy saving. Toward this question, this paper studied the optimization of large scale heating and cooling network. The components of the system are analyzed and modeled in detail including heating/cooling source, heating/cooling users and transmit system. And the system can be optimized through the way of Life Cycle Cost, which compared the cost of large scale heating and cooling system with conventional system. The optimization also takes efficiency and economy in to consideration.

This paper discussed the optimization of two cases of large scale heating and cooling system. One is the heating/cooling system with heating/cooling source with distance from load center, the other is the heating/cooling system with heating/cooling source located in the load center. The affect of the temperature difference between supply and return water, load density and the price of energy towards optimized radius and max radius was discussed using the existed model. The optimized radius and appropriate system parameters are got. It is a reference to the designers and operators related.

As an advanced heat metering method, on-off valve regulation method has good temperature-control and energy-saving effects. But its hydraulic regime is different from other existing systems, the conditions are more complicated and researches are not enough. There is an opinion that differential pressure valve should be used in the buildings consumer heat inlet. For all the questions and uncertainties, this article conducted researches by field test and program simulation analysis. The field test was conducted in a housing estate in Beijing, one buildings flow regulations influence on other buildings hydraulic regime was tested. The simulation was done in HACNet hydraulic simulation software. A pipe net model was built to simulate different working conditions. Both results indicate that systems hydraulic regime is stable and differential pressure valve is not necessary.