The effects of direct and indirect airflow on thermal comfort

A spot cooling system using the convective cooling effect of an air stream is known to beeffective by its smothering intensive hot environment, supplying comfort sense and utilizingenergy efficiently. However, its study on the interaction with human body or product itself isuncommon, showing that the spot cooling system intrinsically contains the possibility ofdraught because of its short emitting distance from the object, low air temperature, high airstream velocity and its direct local contact to human body.

Energy efficiency and IAQ - Simultaneous improvements in relocatable classrooms.

The aim of that study was to demonstrate the potential to design buildings that can simultaneously improve indoor environmental quality along with a reduction of energy. In that order 4 energy-efficient relocatable classrooms were designed and constructed, each equipped with two different HVAC systems (heat-pump air-conditioning system and an energy-efficient indirect/direct evaporative cooler). Results are presented.

Demonstrating automated faults detection and diagnosis methods in real buildings

The objective of the annex 34 was to develop HVAC fault detection and diagnosis tools, which are closed to commercial products. The approach was to design a number of different computer based demonstration systems that could be interfaced to HVAC processes in buildings. By monitoring the operation of these demonstration systems, researchers were able to test a variety of fault detection and diagnosis methods and technique in a real environment, find possible shortcomings and obtain new ideas for further development.

Two-objective online optimization of supervisory control strategy

The set points of supervisory control strategy are optimized with respect to energy use and thermal comfort for existing HVAC systems. The set point values of zone temperatures, supply duct static pressure, and supply air temperature are the problem variables, while energy use and thermal comfort are the objective functions. The HVAC system model includes all the individual component models developed and validated against the monitored data of an existing VAV system.

System interactions in forced-air heating and cooling systems. Part 2 : continuous fan operation

The purpose of continuous fan operation is to bring in fresh outdoor air to the conditioned space in order to maintain acceptable indoor air quality. Ventilation not only uses more energy, but it also impacts air distribution system efficiency.This is partially due to various system interactions. The objective of this paper is to quantify the impact of continuous fan operation on energy use and distribution efficiency by introducingtwo new parameters: energy use ratio (EUR) and distribution efficiency ratio (DER).

Energy conservation benefits of a dedicated outdoor air system with parallell sensible cooling by ceiling radiant panels

Dedicated outdoor air systems (DOAS) integrated with ceiling radiant cooling panels as a parallel sensible cooling system are being considered as an alternative to conventional variable air volume (VAV) systems for commercial buildings because of their energy conservation, first and operating costs, and indoor air quality advantages. A pilot DOAS/radiant panel cooling system is being constructed on a university campus to investigate its advantages over alternative cooling systems in

Performance test results for large coupled indoor/outdoor environmental simulator (C-I/O-ES)

This paper provides a summary of the methods and results of performance testing for a coupled Indoor/Outdoor Environmental Simulator (C-I/O-ES). The simulator consists of an IEQ chamber, a climate chamber, and a replaceable separation/test wall assembly. Both chambers have stainless steel interior surfaces and are equipped with independent heating, ventilating, and air-conditioning (HVAC) systems for simulating indoor and outdoor thermal and air quality conditions, respectively.

Improve energy and comfort performance of large office buildings using integrated interior and exterior zone air-handling units

The interior zone and exterior zone air-handling units (AHU) can be connected through their return air ducts to become a new air-handling unit system, named OAHU system, which allows optimal choice of outside air intake and decouples sensible and latent cooling in a zone with lower sensible

Stabilization of supply air temperature by using granulated phase change materials and application to ventilation system of a house during summer

The authors have proposed a system for stabilizing air temperature using direct heat exchange between granulated phase change materials (PCM) and air. This paper describes experiments in which air whose temperature is periodically changed to simulate changes of outdoor air temperature is passed through a bed of granulated PCM. These experiments demonstrate that output air temperature is stabilized and remains within the phase change temperature range. Results calculated by a computer simulation program described in a previous paper duplicate the experimental results.

Office cooling with air or with chilled beams from an energy perspective

Even in cold climates, offices normally need to be cooled due to the internal heat loads from people, equipment and lighting. Either a chilled ceiling or chilled beams with cooled water as medium or chilled air can be used. In the case with chilled ceiling or chilled beams, a constant air volume system (CAV) is used. In the case of air only, a variable air volume (VAV) system must be used. This paper presents the advantages of the two methods of cooling with respect to energy use, which was calculated from climate data.