Search results for "HV"
showing 10 items of 353 documents
Thermal comfort condition assessment in test buildings with different heating/cooling systems and wall envelopes
2017
Abstract The main aim of this study is a comprehensive analysis of long-term monitoring data of thermal comfort and discomfort parameters in small identical test buildings equipped with different heating/cooling systems. Calculations of PPD index expressed the human perception of thermal comfort and such discomfort factors like draught rate and vertical air temperature difference are provided for the room in winter season running three different heating systems – electric heater, air-air heat pump and air-water heat pump, as well as for the summer cooling with split type air conditioning systems. It is shown that the type of heating/cooling system and its working regime has a significant im…
Comparing different control strategies for indoor thermal comfort aimed at the evaluation of the energy cost of quality of building
2010
Abstract The rapid improvement in the standard of living requires more detailed and sophisticated methods of evaluating comfort conditions. But, maintaining thermal comfort conditions in confined environments may require complex regulation procedures and the proper management of heating, ventilating and air conditioning (HVAC) systems. In turn, the requirements for indoor thermal comfort do not necessarily coincide with those of energy saving purposes, which in the last years are becoming a crucial issue owing to the enactment of the European Energy Performance of Buildings Directive (EPBD). The aim of this work is to compare different indoor control thermal comfort strategies in view of th…
Advanced Control Structure for Energy Management in Ground Coupled Heat Pump HVAC System
2008
Abstract Over the last 15 years, computerized controls have become more and more common in our homes. The smart home looks at expanding the use of the computers into the difference parts of the home, creating a network that can be easily and conveniently controlled. The use of computer controls removes the need to actually flick a switch and allows elements of the home to respond automatically to the people living in it. Successful control and heating ventilating and air-conditioning (HVAC) systems is a primary concern in building project: in order to achieve the required comfort and energy efficiency goals, a lot of variables must be coordinated and kept at particular pre-designed operatio…
Optimization of hybrid – ground coupled and air source – heat pump systems in combination with thermal storage
2010
Ground coupled heat pumps are attractive solutions for cooling and heating commercial buildings due to their high efficiency and their reduced environmental impact. Two possible ideas to improve the efficiency of these systems are decoupling energy generation from energy distribution and combining different HVAC systems. Based on these two ideas, we present several HVAC configurations which combine the following equipments: a ground coupled heat pump, an air to water heat pump and a thermal storage device. These HVAC configurations are linked to an office building in a cooling dominated area in order to evaluate in these conditions the total electrical consumption of each configuration to o…
A cellular automaton based model simulating HVAC fluid and heat transport in a building. Modeling approach and comparison with experimental results
2010
A discrete model characterizing heat and fluid flow in connection with thermal fluxes in a building is described and tested against experiment in this contribution. The model, based on a cellular automaton approach, relies on a set of a few quite simple rules and parameters in order to simulate the dynamic evolution of temperatures and energy flows in any water or brine based thermal energy distribution network in a building or system. Using an easy-to-record input, such as the instantaneous electrical power demand of the heating or cooling system, our model predicts time varying temperatures in characteristic spots and the related enthalpy flows whose simulation usually requires heavy comp…
Parameterization of a comprehensive explicit model for single-ring infiltration
2021
International audience; Comprehensive infiltration models can simultaneously describe transient and steady-state infiltration behaviors, and therefore can be applied to a range of experimental conditions. However, satisfactory model accuracy re- quires proper parameterization, including estimating the transition time from transient to steady-state flow conditions (τcrit). This study focused on improving the estimation of two parameters – τcrit and a second constant called a – used in a comprehensive, explicit, two-term model for single ring infiltration (hereafter referred to as the SA model). Different studies have recommended that a should be as low as 0.45 to as high as 0.91. Furthermore…
Contribution of raindrop impact to the change of soil physical properties and water erosion under semi-arid rainfalls
2017
Soil erosion by water is a three-phase process that consists of detachment of soil particles from the soil mass, transportation of detached particles either by raindrop impact or surface water flow, and sedimentation. Detachment by raindrops is a key component of the soil erosion process. However, little information is available on the role of raindrop impact on soil losses in the semi-arid regions where vegetation cover is often poor and does not protect the soil from rainfall. The objective of this study is to determine the contribution of raindrop impact to changes in soil physical properties and soil losses in a semiarid weakly-aggregated agricultural soil. Soil losses were measured und…
Optimization and Improvement of a Novel HVOF Process Fueled with Ethanol
2022
The high velocity oxy-fuel (HVOF) spray has become a process of choice for producing high performance cermet or alloy coatings. Common HVOF thermal spray systems classically use the combustion of gases, such as hydrogen, propane or a liquid fuel such as kerosene. However, there is currently a limited amount of literature on the use of ethanol as a fuel within HVOF processes and the performances of the resulting coatings are not well documented. Ethanol benefits from environmentally friendly features and is less polluting compared to conventional fossil liquid fuels (i.e. kerosene) as its combustion generates less nitrogen oxides and soot particles. In this work, we decide to investigate suc…
Instrumental calculation, cognitive role-playing, or both?: self-perceptions of Seconded National Experts in the European Commission
2011
This is the authors’ final, accepted and refereed manuscript to the article Most work studying micro-processes of integration – i.e. how agents develop identities and decision-making behaviours within a particular institution – offers explanations based on either instrumental rationality or socialisation. This article proposes a two-dimensional framework that allows analysing under which conditions both logics of social action co-exist. Our empirical analysis employs a unique dataset from a 2011 survey of all 1098 currently active Seconded National Experts (SNEs) in the European Commission. We find that a) instrumental cost-benefit calculation and cognitive role-playing (as semi-reflexive s…
Over 30% of Patients with Splenic Marginal Zone Lymphoma Express Distinctive Antigen Receptors Utilizing a Single Immunoglogulin Variable Gene: Impli…
2010
Abstract Abstract 634 We systematically explored the immunoglobulin (IG) gene repertoire in 337 cases with splenic marginal-zone lymphoma (SMZL), by far the largest series yet. To resolve classification uncertainties, we included in the analysis only cases with a diagnosis of SMZL based on spleen histopathological findings or cases fulfilling the 2008 SBLG criteria (Matutes et al. Leukemia 2008). We here report that the IG heavy variable (IGHV) gene repertoire in SMZL is remarkably biased, with only three genes accounting for 45.8% of cases (IGHV1-2, 24.9%; IGHV4-34, 12.8%; IGHV3-23: 8.1%, respectively), significantly extending previous similar observations. Particularly for the IGHV1-2 gen…