Reductions in fossil fuel use and increases in system efficiency are required to make space heating more environmentally benign. Ground loop heat pumps offer an alternative heating solution that is more environmentally benign than conventional methods. Past studies of these heat pumps have usually focused on basic system arrangements, but new advanced systems are being developed. Here, energy a...

Non-furnace boilers can improve the efficiency of industrial once-through boilers. However, temperature non-uniformity occurs in economizer connected vertically to boiler. Heat transfer performance is degraded by non-uniformity. To solve this problem, a corbel was installed on side wall economizer, and baffle transition duct. Consequently, although thermal boiler improved, significant still obs...

The economizer principle is a well-known method to reduce the expansion losses of a refrigeration system. The alternative refrigerant CO2 has a relatively large isentropic exponent. Therefore it has a high potential for raising efficiency by application of this principle. Reciprocating piston compressors are favored for CO2 refrigeration applications due to their small sealing length and theref...

The complex structure of double inlet gas flue has a significant influence on flow field distribution in 1000MW coal-fired boiler’s low temperature economizer. In order to optimize the economizer with flues and reduce its failure rate, this paper presents simulation based computational fluid dynamics (CFD). This numerical was operated by using porous media model instead inside heat exchanger st...

This paper first analyzes that the waste heat before flue gas of thermal power company enters desulfurizationwer can be heated by low pressure economizer, and then condensate incorporated into regenerative system, so as to recover improve unit efficiency. In this paper, possible lay-out scheme economizer in system is constructed firstly, mathematical model equivalent enthalpy drop increment est...

Energy efficiency of the HVAC system can be improved through renovation and operating method improvement. Economizer control, one energy efficient measures improvement method, introduces outdoor air when is sufficient for cooling. There are high/low limit that determine range economizer control mixed temperature as set-points. controlled with user's or manager's experience, set-point operated f...

We study the problem of heating, ventilation, and air conditioning (HVAC) control in a typical commercial building. We propose a model predictive control (MPC) approach which minimizes energy use while satisfying occupant comfort constraints. A sequential quadratic programming algorithm is used to efficiently solve the resulting bilinear optimization problem. This paper presents the control des...