Product design: Formulation of a screen-printable sintering-type conductive paste

Due to the complexity of the screen-printing operation and the rheological behaviors of the screen-printable paste, such a paste is usually formulated by trial-and-error. In this report, a systematic procedure, based on heuristics and mechanistic models, for the design of a screen-printable paste is developed. The procedure is demonstrated by a case study of the formulation of a conductive paste of copper particles.     

Investigation of the subjective response to elevated air velocities: climate chamber experiments in Hong Kong

It has been suggested that fans be installed in some train stations and workshops to improve the thermal environment. Before doing so, a set of preliminary experiments on the human responses to draughts at elevated temperatures was performed and is reported in this paper. Twenty people were exposed to an air jet with varying speed in a climatic chamber. Their feelings towards the air draught were surveyed and recorded. For higher values of air speed, some of them felt draught would give a comfortable feeling at higher temperatures. The results of this study support the idea of installing fans in some train stations and workshops. Furthermore, an equation on predicting the percentage of people feeling less comfortable was derived by modifying the percentage of dissatisfied in an equation proposed by Fanger et al. to account for this positive feeling of air draught, or beneficial air movement, in places with hot climates.     

Simulation and experimental investigation of two hybrid solar domestic water heaters with drain water heat recovery

In this paper, the performance of two solar domestic hot waters (SDHW) with drain water heat recovery (DWHR) units is investigated. Both SDHW systems are recently installed at the Archetype Sustainable Twin Houses at Kortright Center, Vaughan, Ontario. The first SDWH system in House A consists of a flat plate solar thermal collector in combination with a gas boiler and a DWHR unit. The second SDHW system in House B includes an evacuated tube solar collector, an electric tank, and a DWHR unit. Both systems are modeled in TRNSYS, and the models are validated by experimental data. The addition of the DWHR and the flat‐plate solar thermal collector would result in 1831 kWh of annual energy saving in House A. While the addition of the DWHR and the evacuated tube collector in House B would result in an annual energy saving of 1771 kWh. Subsequently, the models are used to investigate the performance of similar systems for five major Canadian cities of Halifax, Montreal, Toronto, Edmonton, and Vancouver. The conjunctions of solar thermal collectors with DWHR units are found most beneficial in Edmonton. It is also noted from experimental and simulated results that flat‐plate solar collector‐based water heater produced more thermal energy than the system based on the evacuated tube solar collector for all major Canadian cities. Copyright © 2015 John Wiley & Sons, Ltd.