Almost half of the total energy used in the U.S. buildings is consumed by heating, ventilation and air conditionings (HVAC) according to EIA statistics. Among various driving factors to energy performance of building, operations and maintenance play a significant role. Many researches have been done to look at design efficiencies and operational controls for improving energy performance of buil...

This paper presents an occupancy-predictive control method for heating, ventilation, and air conditioning (HVAC) systems in buildings that incorporates the building’s thermal properties, local weather predictions, and a self-tuning stochastic occupancy model to reduce energy consumption while maintaining occupant comfort. Contrasting with existing approaches, its occupancy model requires no man...

A new inverse method is proposed for estimation of thermal inertia and heat gain in air conditioning and refrigeration systems using on-site temperature measurements. The method is applied on a walk-in freezer room of a restaurant in Surrey, British Columbia, Canada during one week of its regular operation. The thermal inertia and instantaneous heat gain are calculated and the results are valid...

A chilled water system transports cooling functionality from refrigerators to users via heating, ventilation, and air conditioning (HVAC) systems. This paper investigated an optimal control strategy regulate the volume flow rate of each user branch in a system, considering minimum resistance operation reduce energy consumption. An artificial neural network (ANN) was adopted establish nonlinear ...

0002-9610/$ see front matter 2014 http://dx.doi.org/10.1016/j.amjsurg.20 Abstract BACKGROUND: Prophylactic incisional negative-pressure wound therapy use after ventral hernia repairs (VHRs) remains controversial. We assessed the impact of a modified negative-pressure wound therapy system (hybrid-VAC or HVAC) on outcomes of open VHR. METHODS: A 5-year retrospective analysis of all VHRs performed...

Poorly maintained, degraded, and improperly controlled equipment wastes an estimated 15% to 30% of energy used in commercial buildings. Much of this waste could be prevented with widespread adoption of automated condition-based maintenance. Automated fault detection and diagnostics (FDD) along with prognostics provide a cornerstone for condition-based maintenance of engineered systems. Although...

Performance of building Energy Management Systems (EMS) has been controversial in several studies due to lack of measured energy savings, changes in building use or operation, other changes that simultaneously affect building energy use, equipment malfunction, or weather normalization. This study evaluated energy savings in 20 buildings that have EMS installed to control HVAC. The buildings wer...