Control strategies study of a complete solar assisted air conditioning system in an office building using TRNSYS

(2009, September)

It is now clearly assumed that solar assisted air conditioning is able to minimize environmental impact and CO2 production of buildings operation. How to reach highest energy savings is still a work in ... [more ▼]

It is now clearly assumed that solar assisted air conditioning is able to minimize environmental impact and CO2 production of buildings operation. How to reach highest energy savings is still a work in progress. In former literature, equipment control has been point out as a critical feature of energy consumption. Control becomes more and more important as system is complex. The complete simulation environment was developed in previous work, it includes the absorption chiller itself, the rejection circuit (cooling tower), solar panels field, heater, storage device, pumps, heating-cooling networks, emission system and building. TRNSYS software modular approach provides the possibility to model and simulate this complete system. In this article, different strategies are proposed to minimize consumption for air-conditioning. [less ▲]

Thermal modelling of the cooling ceiling system as a commissioning tool.

(2009, August)

This paper presents the results of a study performed to develop a computational model of cooling ceiling systems. This one has to be used in situ, as diagnosis tool in commissioning process in order to ... [more ▼]

This paper presents the results of a study performed to develop a computational model of cooling ceiling systems. This one has to be used in situ, as diagnosis tool in commissioning process in order to determine the main operating conditions of the system in cooling mode. The model considers the cooling ceiling as a fin. Only the dry regime is considered. From ceiling and room dimensions, material description of the cooling ceiling and measurement of supply water mass flow rate and air and water temperatures, the model calculates the cooling ceiling capacity, ceiling surface average temperature and water exhaust temperature. Fin efficiency, mixed convection close to the cooling ceiling (generated by the ventilation system) and panel perforations influence are studied. A series of tests and experimental results on four types of cooling ceilings are used in order to validate the model. [less ▲]

Dynamic simulation of a complete solar assisted air-conditioning system in an office building using TRNSYS

(2009, July)

Analysis of building heating and cooling demands in the purpose of assessing the reversibility and heat recovery potentials

Report (2008)

Performance assessment of heat pump systems in non-residential buildings by means of dedicated simulation models

Poster (2008, September)

Building and HVAC system simulation with the help of an engineering equation solver

in Proceedings of the 3rd National conference of the IBPSA-USA, Berkeley, CA (2008, July)

A simplified Building-HVAC system model is presented here. It includes simplified models of building zone and of HVAC equipment. The simplified building zone model is based on a R and C network, whose ... [more ▼]

A simplified Building-HVAC system model is presented here. It includes simplified models of building zone and of HVAC equipment. The simplified building zone model is based on a R and C network, whose parameters are adjusted trough a frequency characteristic analysis. The implementation of the classical phenomena taking place in building dynamics is discussed. The simplified building model is compared with more detailed models, using the BESTEST procedure. The application of the presented model to the audit of commercial buildings is also discussed. [less ▲]

Heat pumping and reversible air conditioning : how to make the best use of HVAC equipment ?

Conference (2008)

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced ... [more ▼]

Substituting a heat pump to a boiler may save more than 50% of primary energy, if electricity is produced by a modern combined cycle power plant (and even more if a part of that electricity is produced using renewable sources). Two of the most attractive heat pumps applications consist in recovering the heat rejected by the condenser of an existing chiller and in using this chiller in reversible mode. This is the topic of the IEA-ECBCS Annex 48 project (“Heat pumping and reversible air conditioning”). An overview of the project is presented and the work of the different participants is briefly explained. Case studies are also briefly presented and more details are given on one of them. [less ▲]

From model validation to production of reference simulations: how to increase reliability and applicability of building and HVAC simulation models

in Building Services Engineering Research & Technology (2008), 29(1), 61-72

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA ... [more ▼]

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA Annex 34/43 originally targeted a number of specific applications where a more advanced validation was required: ground coupling problems, multizone building, shading, day lighting and cooling load interaction, HVAC components and ventilated facades. These validation exercises were built on the large methodological experience obtained in previous projects and address sometimes very fundamental problems of heat transfer in buildings. Consulting engineers and practitioners might see these exercises as a bit too far from their objectives and it is the reason why an additional activity was proposed with the specific aim of producing, based upon the results of the validation of models, a set of reference simulations. These applications cover a range of building types (residential, commercial) and systems (production, distribution emission) and run in a variety of climates. The paper will describe how models dedicated to these applications were developed, starting from validation results, going through the selection and consolidation of simulation hypothesises and ending with a number that might be considered as reference for the concerned applications. The paper will concentrate on models required by a residential building application (multizone building equipped with a heat pump or a condensing boiler, heat emitted by radiators or floor heating systems). Simulations make use of both EES and TRNSYS software and both software are applied in parallel as far as possible in the different applications in order to get a better judgment of their potential advantages and drawbacks. The use of reference simulations in view of qualifying normative methods currently in development in the frame of the European Energy Performance in Buildings Directive is also addressed and demonstrated in the paper. [less ▲]

Friendly simulation of residential heating systems.

Conference (2007, June)

Until now, the choice of a heating system is, in most cases, rather intuitive, but not based on significant comparisons among the many options available on the market. Friendly calculation tools are badly ... [more ▼]

Until now, the choice of a heating system is, in most cases, rather intuitive, but not based on significant comparisons among the many options available on the market. Friendly calculation tools are badly needed. A prototype of simulation model is shortly presented in this paper. It is designed as a preliminary design tool, allowing the different partners of a project to evaluate the energy impact of the very first design options: building envelope heat transfer coefficients, glazing areas, orientations, solar factors, ventilation mode, heat emission, distribution, generation and control strategy. The heating demand is calculated hour by hour with consideration to the time variations of inside and outside temperatures and free gains, to the control law and to the heating power actually available. The emitter is a water-ambient heat exchanger. It may have some thermal mass. Two emitters are here proposed: the radiator and the flow heating system. A steady state water distribution model is included in this simulation; it takes heat losses in unheated spaces into account: Three typical heating sources are proposed: classical boiler, condensing boiler and heat pump. All heat generators are here simulated with the help of very simple polynomial (“daughter”) models. The polynomial expressions are fitted on the simulation results obtained with reference (“mother”) models, themselves fitted on experimental data available. Examples of simulation results are presented in the paper. [less ▲]

From model validation to production of reference simulations: how to increase reliability and applicability of building and HVAC simulation models

(2006, December)

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA ... [more ▼]

Validation of simulation models appears from a long time as a key issue in order to promote a more intensive and more efficient use of simulation models in the field of building and HVAC simulation. IEA Annex 34/43 originally targeted a number of specific applications where a more advanced validation was required: ground coupling problems, multizone building, shading, day lighting and cooling load interaction, HVAC components and ventilated facades. These validation exercises were built on the large methodological experience obtained in previous projects and address sometimes very fundamental problems of heat transfer in buildings. Consulting engineers and practitioners might see these exercises as a bit too far from their objectives and it is the reason why an additional activity was proposed with the specific aim of producing, based upon the results of the validation of models, a set of reference simulations. These applications cover a range of building types (residential, commercial) and systems (production, distribution emission) and run in a variety of climates. The paper will describe how models dedicated to these applications were developed, starting from validation results, going through the selection and consolidation of simulation hypothesises and ending with a number that might be considered as reference for the concerned applications. The paper will concentrate on models required by a residential building application (multizone building equipped with a heat pump or a condensing boiler). Simulations make use of both EES and TRNSYS software and both software are applied in parallel as far as possible in the different applications in order to get a better judgment of their potential advantages and drawbacks. The use of reference simulations in view of qualifying normative methods currently in development in the frame of the European Energy Performance in Buildings Directive is also addressed and demonstrated in the paper. [less ▲]