This paper shows how air-to-air heat and energy system design problems can be formulated for a simple HVAC configuration and solved for the least life-cycle cost system while still retaining a small payback period. Mathematical expressions and design tables are presented to facilitate the design process. The design process is illustrated for the city of Chicago where both large heating and cooling loads occur in HVAC applications. The example design problem presented shows that
Diagnosing occupant complaints is not an easy task. The following article is a guide for engineers and owners confronted with hot/cold problems. It advises how to evaluate the occupant's complaint (with seven questions), then to review the HVAC equipment performances for a proper operation, to make load calculations, to review zoning conflicts and draft problems, to measure the humidity level, and the omni-directional drafts.
Modern buildings’ environmental impacts threaten global environmental health. Population growth and increased access to and use of current building technology are not sustainable. People are often not in control of their building environments and, as a re
The control industry integrates more and more recent innovations, especially on the sector of communication networks (bus), control (fuzzy logic, neural networks...) and informatics (hard-and software) for the development of Building Automation and Control Systems of HVAC plants. These complex control strategies are now being implemented on ventilation systems (hybrid systems, mechanical systems, etc) to satisfy energy and environmental issues.
In the 1970's variable-air-volume (VAV) revolutionized the use of air-conditioning for commercial buildings. Now a new revolution is underway with the ductless VAV systems.This article describes the two main types of ductless VAV systems (underfloor and overhead) and explore their benefits such as easier design, lower energy consumption, reduced building-faade costs, improved air quality.
Buildings leak water and air : it is normal and impossible to avoid. So the architect and HVAC engineer's goal should be to recognize the concept of building air leakage and account for it in :- quantifying leakage- reducing it if excessive- controlling leakage by managing air pressures with the HVAC system.The aim of this article is to discuss the methods for measuring and expressing leakage and to report the results of a cas study, San Carlos Park elementary school in Fort Myers, Florida.
The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. Each floor is designed to be cross-ventilated, through upper windows that are controlled by the building management system (BMS). Users have control over lower windows, which can be as much as 50% of the total operable area. There are significant differences in the performance and the control of the windward and leeward sides of the building, and separate monitoring and control strategies are determined for each side.
The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. The EnergyPlus thermal simulation program was used to evaluate different ventilation strategies for space cooling and rationalize the design of the faade. The strategies include ventilation driven by different combinations of wind, internal stack and external stack. The simulation results indicate that wind-drive ventilation can maintain adequate comfort even during hot periods.
At the new institute building of Fraunhofer ISE, both mechanical and free night ventilation is used for passive cooling of the offices. The results from a monitoring of room temperatures in 21 office rooms during summer 2002 show that room temperatures exceeds 25 C in less than 8 % of the working hours, even at high ambient air temperatures. In two offices, experiments were carried out in order to determine the efficiency of night ventilation dependent on air change rate, solar and internal heat gains. During the experiments, meteorological data, air change rates, air temperatures (incl.
The necessity of focus on more large integration of passive concepts for indoor climate conditioning is today a reality. Through this study, a contribution to fill the lack of useful design guidelines for natural ventilation is proposed, in order to develop the passive ventilation systems implementation. Besides a methodological approach, the paper proposes conceptual tools. The implementation of a natural ventilation strategy includes the envelope building design, the indoor spaces layout and the