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Part-time vocational engineering curricula aim to transform experienced higher technicians into engineering managers. This is done by making use of previous experience in working positions and adding training in new situations. Job training is combined with academic training through courses and activities at an academic institution. Describes ways to achieve synergy between the two streams. (PVD)

Energy performance contracts (EPC) are types of agreements in which a service provider guarantees that customers' buildings will achieve a specified energy performance (i.e., minimum energy savings) to reduce the risk of their investment in energy efficiency improvements. EPC requires prediction of future energy consumption of the building, at the design stage, before construction or major retrofit. To this end, building energy simulations taking into account all the major energy-using components are performed. In particular, fans can contribute significantly to the total building consumption. The overall efficiency of fans is the combination of three factors: mechanical, motor, and variable frequency drive (VFD). Manufacturers usually provide fan mechanical efficiency curves for a broad operating range. In contrast, motor and VFD efficiencies are generally given at rating conditions only. To represent part-load conditions, correlations are typically used to estimate motor and VFD efficiency variations, to evaluate the overall electricity consumption. The first aim of this study is to evaluate existing correlations for motor and VFD efficiency as a function of load and speed, by comparison with manufacturer data, for a vendor that has shared its detailed test data. While VFD efficiency correlations from the literature provide reasonable accuracy against real data, motor correlations under predict actual motor efficiency at low loads. The second aim of the paper is to improve such correlations using Bayesian inference to fit the available data. [ABSTRACT FROM AUTHOR]

Determining the on-field heating capacity and coefficient of performance (COP) of residential air-to-air heat pumps (HPs) is problematic, given that measuring accurately the enthalpy and, specifically, the mass flow rate of air is challenging. This paper validates a promising on-field performance measurement method for HPs with an internal heat exchanger (IHX) as vapor injection system using experimental data obtained from air-to-water heat pump prototype in several operating conditions. The method is based on refrigerant fluid measurements and component energy/mass balances. Nonintrusive sensors, such as surface temperature sensors, are used to estimate pressure and refrigerant mass flow rate in different types of heat pump systems, including air-to-air. Obtained results compared with intrusively measured reference values in steady-state conditions are in good agreement, suggesting that a comprehensive performance analysis can be conducted in already-installed high efficiency residential IHX air-to-water HPs, as well as internal heat exchanger air-to-air HPs. [ABSTRACT FROM AUTHOR]

The decrease in heat demand in low energy buildings and the development of new heating, ventilation and air conditioning systems call for a re-examination of the usual modelling approaches in building simulation. A comparison methodology is developed to confront different modelling approaches with experimental data. The methodology is applied to four models of variable speed air-to-air heat pumps. Two classical empirical models (a static and a dynamic one) and a detailed physical model are selected. Moreover, a simplified physical model is developed for this study. The detailed control of the experimental heat pump and a model of the defrost cycle are given. The four modelling approaches are compared toin situmeasurements for outdoor temperatures betweenandincluding defrost phases. The simulation results are analysed from the point of view of building energy simulation. [ABSTRACT FROM PUBLISHER]

Quantification of the effects of combined variations of building and system parameters on energy consumption requires a large number of simulations and time-consuming analysis of obtained results. The use of experimental designs is a practical solution to this problem. The experimental designs are used to express the energy consumption of a building by a polynomial expression which represents the effects and interactions of different parameters. The polynomial models derived from an energy consumption simulation tool are highly precise in their predictive ability with respect to the tool itself. In this report, the resulting non-dimensional models of different building types in different climates are created and assembled in a database. This database is a fast tool for selection and comparison of technical solutions by designers and contractors. These experimental models are useful for consulting and assistance with decision making and are easily expandable for techno-economical optimization. [ABSTRACT FROM AUTHOR]

This article focuses on a particular type of horizontal ground heat exchangers (HGHE) which can be used as a heat source (or heat sink) for geothermal heat pumps. It consists of a long pipe buried about 1 m below the ground surface and arranged in parallel regularly spaced sections, forming a serpentine. This article proposes a model for such a heat exchanger, where the serpentine is discretized axially and a three-step calculation procedure is performed on each node. The axial fluid temperature variation in the pipe is first computed by using an implicit numerical resolution scheme. Then, heat transfer in the ground surrounding the pipe is obtained by using the analytical cylindrical heat source solution. In the third step, used for mid- to long-term simulations, thermal interference between parallel pipe sections is taken into account using spatial superposition. Finally, these solutions are coupled iteratively to obtain the axial fluid and pipe temperatures at each time step. The model is then validated using a full-scale experimental facility located in Orléans, France. Following a brief description of the facility, validation results are reported. The main validation test consists of supplying the HGHE with a constant inlet fluid temperature (40°C [104°F]) for a 200-h period in soil at an initial temperature of 7.5°C (45.5°F). After an initial transient period, the recorded outlet fluid temperature matches the model prediction within 1°C (1.8°F). [ABSTRACT FROM AUTHOR]

Abstract: A desiccant wheel model has been developed in the aim to be adapted to building simulation tools. This model fulfils several criteria such as simplicity of parameterization, accuracy, possibility to characterize the equipment under all operation conditions and low computation time. The method of characteristics has been applied to the heat and mass transfer partial differential equations. This transformation provides new equations which are similar to those of a rotary heat exchanger. Then, the model is described by the Effectiveness-NTU method and it is identified from only one nominal rating point. The model has been compared to experimental and manufacturers’ data for a broad range of operating conditions. A good agreement has been found. [Copyright &y& Elsevier]

Abstract: A desiccant-wheel behavioural model has been developed. This model fulfils several criteria, such as simplicity of parameterization; accuracy; ability to characterize the equipment behaviour under all operation conditions; and short computation time. The method of characteristics has been applied to the heat-and-mass transfer partial-differential equations. This transformation provides equations which are similar to those of a rotary heat-exchanger. Then, the model is described by the effectiveness-NTU method and identified from only one nominal-rating point. The model predictions have been compared with experimental and manufacturers’ data for a broad range of operating conditions. Good agreement has been found. [Copyright &y& Elsevier]

A simplified model for indirect cooling towers behaviour is presented. The model is devoted to building simulation tools and fulfils several criteria such as simplicity of parameterisation, accuracy, possibility to model the equipment under various operation conditions and short computation time. On the basis of Merkel''s theory, the model is described by using the Effectiveness-NTU method. The model introduces only two parameters, air-side and water-side heat-transfer coefficients which can be identified from only two rating points, data easily available in manufacturers'' catalogues. Thus, the model allows one to estimate energy and water consumptions under different operating conditions such as variable wet-bulb temperatures or variable airflow rates. [Copyright &y& Elsevier]

Presents a discussion on NFI, an engineering curricula in France that aims to train higher technicians as engineers through vocational education. Importance of a capacity of synthesis for an engineer; Student engineers' need to acquire unfamiliar skills; Preparation of the engineer's thesis.