Heat Transfer In Naturally Ventilated Rooms: Data From Full-Scale Measurements.

Experiments were conducted in a full-scale room of the Florida Solar Energy Center (FSEC) Passive Cooling Laboratory (PCL) to determine heat-transfer coefficients from one vertical wall when the room was naturally ventilated. Such data are required for accurate predictions of heat removal rates from overheated rooms by natural and forced ventilation. The heat-transfer data are correlated to local surface airspeeds and design values are presented. Comparisons are made with other data sources

Analytical assessment of the desiccant enhanced radiative cooling concept

This paper provides a limited analytical feasibility assessment of the desiccant enhanced nocturnal radiation (DESRAD) cooling and dehumidification concept. This concept integrates the moisture exchanging capacity of a roof plenum desiccant system with radiative cooling potential of the night sky and the thermal and moisture capacity of building materials to provide a high efficiency, daily-cycle cooling and dehumidification system for buildings. The paper presents the modeling methodology and results from an analysis of the DESRAD system in Miami, FL and Atlanta, GA. The model accounts for the interaction of the building and the DESRAD system by coupling a combined heat and mass transfer model for the building and a pseudo steady-state desiccant model for the DESRAD system. Results show summer day electrical cooling savings of 65% and 78% for Miami and Atlanta, respectively. Peak electrical demands over a five hour period from noon to 5 p.m. were also reduced by 20% in Miami and 60% in Atlanta

Combined Heat And Moisture Transfer In Buildings And Structures

Accurate modeling of combined heat and moisture transfer in building systems is important in predicting the indoor conditions, loads, comfort levels, degradation and deterioration of building components, and performance of mechanical equipment. Several approaches can be taken to study the combined heat and moisture transport behavior of building materials. This paper describes a simplified approach of modeling moisture transport in buildings. The building domains, energy and moisture balance equations involving moisture adsorption and desorption of building materials are discussed in detail. The assumptions, parameters required and limitations of the model are also addressed. A public domain program, TRNSYS 12.2, is modified using the model developed in this paper

Wing Walls To Improve Natural Ventilation: Full-Scale Results And Design Strategies.

A significant design problem arises in ventilating rooms which have only one external wall and, therefore, cannot be normally cross ventilated. Architectural projections called wing walls can be used to effectively ventilate these rooms. The benefit of wing walls from air flow measurements in a full-scale room with and without wing walls is confirmed. Alternative design strategies for incorporating wing wall features in residences are also described

Wingwalls To Improve Natural Ventilation: Full-Scale Results And Design Strategies.

Natural ventilation can be used to cool buildings during many months of the overheated season. A significant design problem arises in ventilating rooms which have only one external wall and, therefore, cannot be normally cross ventilated. Architectural projections called \u27wingwalls\u27 can be used effectively to ventilate these rooms. This paper confirms the benefit of wingwalls from airflow measurements in a full-scale room with and without wingwalls. Alternative design strategies for incorporating wingwall features in residences are also described

Auxiliary Cooling Loads in Passively Cooled Buildings: An Experimental Research Study

Currently accepted methods of passive cooling offset only sensible building loads. In the warm, humid southeastern gulf coast climates the latent building load can comprise 35% of the building load in the typical residence. As the sensible load on residences in these climates is reduced or offset by passive cooling techniques, this latent cooling load percentage increases rapidly. In such residences the auxiliary cooling load cannot be effectively met by conventional cooling equipment . The Florida Solar Energy Center (FSEC) is examining the auxiliary cooling requirements of residences in warm, humid climates. The study addresses both the thermal and moisture response of buildings. A total of eight wall systems, three frame wall types and five concrete block wall types are under test at the FSEC Passive Cooling Laboratory (PCL) in Cape Canaveral. Moisture studies involve examination of the absorption and desorption rates of building materials and furnishings and the development of improved moisture migration modeling techniques for inclusion in building energy analysis programs. TARP (Thermal Analysis Research program), developed at NBS by George Walton, and FLOAD, by FCHART Software, have been chosen as the analysis programs with which cooling examined

A model–based approach to fault–tolerant control

A model-based controller architecture for Fault-Tolerant Control (FTC) is presented in this paper. The controller architecture is based on a general controller parameterization. The FTC architecture consists of two main parts, a Fault Detection and Isolation (FDI) part and a controller reconfiguration part. The theoretical basis for the architecture is given followed by an investigation of the single parts in the architecture. It is shown that the general controller parameterization is central in connection with both fault diagnosis as well as controller reconfiguration. Especially in relation to the controller reconfiguration part, the application of controller parameterization results in a systematic technique for switching between different controllers. This also allows controller switching using different sets of actuators and sensors