Dynamic models of vapor compression systems are important tools for HVAC engineers in the development and evaluation feedback control and fault detection and diagnostic (FDD) algorithms. Significant literature exists on dynamic models of vapor compression systems. Much of it is restricted to air-to-air systems and few papers deal with liquid chillers. Most of existing liquid chiller models revi...

Traditionally, energy recommendations from energy audits have been concerned with the energy use of cooling towers for point of use energy, such as variable speed fans, and pumping savings. The actual energy use of a cooling tower is small, and is only a portion of the energy involved in the entire cooling system. The majority of the energy used is to perform the work necessary to compress the ...

Dynamic models of liquid chillers are gaining importance in recent years as tools for evaluating feedback controllers and to study transient system performance in general. Such system models consist of component models for the heat-exchangers, the compressor and the expansion device. The modeling of the heat-exchangers is particularly significant as they constitute the largest thermal capacitan...

Absorption chillers present opportunities to utilize sustainable fuels in the production of chilled water. An assessment of the steam driven absorption chiller at the University of Idaho, was performed to quantify the current exergy destruction rates. Measurements of external processes and flows were used to create a mathematical model. Using engineering equation solver to analyze and identify ...

This study constructed a parameter analysis for improving the energy performance of air-cooled water chillers by altering the angle configuration of the condenser coils. The mathematical models for energy and exergy analyses of the individual components and overall system of air-cooled water chillers are presented. This study investigated the potential enhancement of performance efficiency in a...

This paper proposes the first application of a split-range control technique on concentrating solar collector to improve an absorption plant production. Solar plants have power availability in phase with cooling demand under design conditions. Thus, it is powerful technology context renewable energy and efficiency. These need systems cope irradiance intermittency, reject irradiation disturbance...

During the last years, special attention has been paid to renewable polygeneration technologies, able of simultaneously producing thermal, cooling, electrical energy and desalinated water from seawater. This paper focuses on an innovative polygeneration system driven by renewable energy sources, including the following technologies: hybrid photovoltaic/thermal collectors, concentrating paraboli...

Performance data obtained from measurements of process variables usually do not obey material and energy conservation laws. This is why a data reconciliation process, that is, the adjustment of measured data to obey the conservation laws and other constraints is necessary in order to characterize the real performance of equipment, processes, or the whole plant. The information on the partial lo...

Component and subsystem models used to evaluate the performance of a low-lift cooling system are described. An air-cooled chiller, a hydronic radiant distribution system, variable-speed control, and peak-shifting controls are modeled. A variable-speed compressor that operates over 20:1 speed range and pressure ratios ranging from one to six is at the heart of the chiller. Condenser fan and chil...