In hot and humid climates, dampness in buildings leads to significant respiratory symptoms and damage to buildings. A damp house can be recognized by one or more of the following characteristics: damp stains, mold growth, condensation, a musty smell or stuffy atmosphere, and insects such as silverfish and sow bugs. To improve this problem, a desiccant cooling system has been suggested as a suitable system to improve indoor air quality (IAQ) by its superior performance of humidity control.
Double-skin facades have been increasingly used as they open up new possibilities for clients and planners seeking creative new designs that are intelligently adapted to environmental conditions. Natural ventilation is commonly carried out in a building with double-skin facades; however, doubleskin facade construction is still not covered by statutory building regulations.
This paper describes the design, simulation, building, and testing of a 10.5 kW (3-ton) residential air conditioner for hot/ dry climates. The unit was optimized to field-measured indoor and outdoor conditions and duct system losses, subject to the same packaging constraints as conventional systems.
A new type of microchannel flat tube plate fin evaporator and condenser were designed and fabricated for this project.
This paper presents an integrated approach to controlling dry-bulb supply air temperature and outside air intake rate of an air-handling unit (AHU) by adopting a model predictive control strategy. The dynamics of the AHU are modeled with a multi-input-multi-output (MIMO) model that has a linear
structure and time-variant gains. The model predictive control (MPC) controller can respond properly to different working conditions by assigning different weighting factors and constraint limits to a convex quadratic optimization problem.
In this paper, the airborne transport characteristics of airflow due to coughing are investigated in a stagnant indoor environment using transient computational fluid dynamics (CFD) analysis on the dispersion of coughed airflow. The dispersion phenomena of the airflows generated by coughing
and exhaling were reproduced based on the unsteady models of coughing and breathing. The concentration simulation was coupled to simulate the dispersion of the coughed air. The simulation results indicate that in a stagnant environment :
The effect of varying inlet air velocity due to a corresponding change in inlet nozzle slot size to achieve a constant slot Reynolds number was investigated in a benchmark room. The primary objective of the project was to evaluate the dependence of turbulence intensity levels in the room upon the air inlet nozzle slot geometry. A stereoscopic particle image velocimetry (SPIV) system was used to measure airflow characteristics for two different air inlet nozzle slot sizes in an irregularly
This paper provides an experimental evaluation of the efficiency of an energy recovery ventilator (ERV) for a range of summer temperatures in Ottawa including humid summer days. The assessment was achieved using the twin houses at the Canadian Centre for Housing Technology (CCHT) and their side-by-side testing to measure the real impact of the installation of the ERV. Side-by-side testing consists of incorporating into the test house an innovative energy-saving component, in this case the ERV. Both houses are then operated identically and monitored.
A new method for optimizing the indoor thermal climate under nonuniform temperature distribution by accounting for energy conservation and indoor thermal comfort has been developed. Temperature settings and arrangements of thermal sensors of an HVAC system are optimized using a genetic
algorithm-based method (e.g., Cantu-Paz 2000). In a genetic algorithm, design variables are coded into a chromosome that is subject to a series of genetic operations in search of an optimized solution. An optimal sensor arrangement requires :
The first goal of this paper is to arm the reader with the knowledge necessary to compare filter performance. In that aim ASHRAE standards 52.1.-1992 and 52.2. - 1999 are described first in general and qualitative terms, then with specific details including equations and examples. An application-level knowledge is provided too via discussion and practical considerations.
This paper discusses the result of a field study undertaken in two phases to evaluate and define the role of various filter efficiencies in attaining and sustaining clean HVAC components and distribution systems. Its conclusion is that filter efficiency is a significant factor in preserving system cleanliness, that low efficiency equals low performance for MERV 6 filters, whereas MERV 15/16 filters appear to be the best of all.
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