The low-flow solar water heater – from 7 litres/hour to 15 litres/hour per solar collector area – is the most promising way for improving the solar water heater performance. This performance can be increased taking advantage of the low flow to obtain a better stratification in the tank. For this purpose, the most promising technology uses a mantle storage tank with injection of the collector fluid at several levels. The aim of this article is to present some numerical and test results from the storage tank of a low-flow solar water heater.
This paper presents a methodology to analyse the thermal loads of non-residential buildings based on simplified weather data, which are available for 206 Brazilian locations. These data include monthly average of maximum and minimum temperatures, atmospheric pressure, cloud cover and relative humidity. For each month, two typical days are used to estimate the cooling and heating loads. The Transfer Function Method was used to run load calculations and the validation was evaluated according to ASHRAE Standard 140.
This paper presents the development of a simulation tool based on the Matlab computational environment for building temperature performance analysis with automatic control. The simulation tool contains mathematical models for buildings, HVAC (Heating, Ventilation and Air Conditioning) systems, sensors, weather data and control algorithms. The building mathematical model is described in terms of statespace variables, with a lumped approach for the room air governing equations – energy and mass balances. In this context, the simulation tool structure and components are explained.
Computer based modeling tools were used to examine the hygrothermal environment inside a heavy-masonry historic building experiencing crypto-efflorescence damage to its moisture-laden brick vault. Monitoring was carried out to investigate the damage pattern against changes in the interior environment and to validate simulation models. The models predicted a period of 1,612 annual hours during which the vault was vulnerable to salt damage under the current environmental regime and a potential reduction of this critical period by 98% as a result of a remedial measure.
This article presents a mathematical model that provides explicit support for preserving the consistency between decisions made at various points during building performance analysis. Analytical Target Cascading, a multilevel engineering design optimization framework, is applied to the energy analysis process. Within this framework, the energy analysis problem is decomposed into hierarchical levels based on individual performance goals. Interactions among all levels in the hierarchy are accounted for by linking them mathematically.
The aim of the European SSHORT (Sustainable Social Housing Refurbishment Technologies) project is to increase and promote rational and efficient use of energy in the retrofitting of social housing buildings. In this scope, one step was to develop a specific multicriteria decision-making tool to support decisionmakers in choosing the most adequate energy technological solutions for refurbishment in Europe. The tool (System Selection Tool) is based on a method for multi-criteria evaluation of combinatorial systems. The tool aims at an energy system as a combination of technical solutions.
This paper describes a newly developed prototype of continuous commissioning tool that can be stand-alone or be embedded in a BEMS to continuously monitor a building’s HVAC systems performance and detect faults during operation phase. The component models are either taken from HVACSIM+, SIMBAD, etc. or newly developed. The tool judge whether there are faults in the systems through comparing the operational data with the performances of the systems without faults obtained from operation records or simulation.
Two dissimilar models capable of predicting the electrical and thermal performance of residential cogeneration fuel cell systems have been developed for use with the ESP-r building simulation program. The first model examines low temperature polymer electrolyte fuel cell (PEFC) systems, while the second model is better suited for the modelling of internally-reforming, high temperature solid oxide fuel cell (SOFC) systems. The models use different approaches to estimate the heat recovered from the fuel cell.
In principal, the algorithms used in advanced lighting simulation software are equally applicable to interior and exterior situations [Ashdown 1994][Ward 1998]. In practice the scope is limited: a realistic CAD model of a building in a complex urban geometry can have two/three orders of magnitude more data elements than a detailed model of a room.
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