Evaluation of a heat pump system for greenhouse heating

Greenhouse heating costs for some commercial growers in southern Australia are now a significant production cost. This is particularly the case for those operators who installed heating systems using liquefied petroleum gas (LPG) when this fuel was relatively inexpensive. Heat pump systems used in various configurations have been suggested as an option for reducing energy use and costs for greenhouse heating, particularly if off-peak electricity is used. This paper investigates the financial and environmental viability of an air-to-water heat pump system for a 4000 m2 greenhouse, located 120 km north of Melbourne, Victoria. The simulation software, TRNSYS, was used to predict the performance of the system. The heat pump system was found to have a simple payback period of approximately six years and reduce LPG consumption by 16%. Greenhouse gas emissions were 3% higher using the heat pump system, compared to the existing LPG boiler.

The uptake of an early warning system in an Australian emergency department : a pilot study

Objectives: To evaluate the uptake of an emergency department early warning system (ED EWS) for recognition of, and response to, clinical deterioration.

Design, setting and participants: A descriptive exploratory study conducted in an urban district hospital in Melbourne, Australia. Systematic sampling was used to identify every 10th patient for whom the ED EWS was activated from May 2009 to May 2011.

Main outcome measures: Patient characteristics, ED system data and ED EWS activation characteristics.

Results: ED EWS activation occurred in 1.5% of ED patients; 204 patients were included in this pilot study. The median age was 65.1 years (interquartile range [IQR], 47.8-77.5 years), 89.2% of patients were classified as triage category 2 or 3, and 82.4% of patients were seen by medical staff before ED EWS activation. Hypotension (27.7%) and tachycardia (23.7%) were the most common reasons for ED EWS activation. Median duration of clinical instability was 39 minutes (IQR, 5- 129 minutes). Nurses made 93.1% of ED EWS activations. Median time between documenting physiological abnormalities and ED EWS activation was 5 minutes (IQR, 0- 20). Most patients (57.8%) required hospital admission: 4.4% of patients required intensive care unit admission.

Conclusions: The ED EWS resulted in at least two formal reports of clinical deterioration in ED patients per day, indicating reasonable uptake by clinicians. A greater understanding of clinical deterioration in ED patients is warranted to inform an evidence-based approach to recognition of, and response to, clinical deterioration in ED patients.

A novel exhaust heat recovery system to reduce fuel consumption

Internal combustion engines release about 1/3 of the energy bound in the fuel as exhaust waste gas energy and another 1/3 energy is wasted through heat transfer into the ambient. On the other hand losses through friction are the third largest root cause for energy loss in internal combustion engines. During city driving frictional losses can be of the same size as the effective work, and during cold start these losses are even bigger. Therefore it is obvious to utilise wasted exhaust energy to warm up the engine oil directly. Frictional losses of any engine can be reduced during part load. Sensitivity analyses have been conducted for different concepts that utilise exhaust energy to reduce engine viscosity and friction. For a new system with an exhaust gas/oil heat exchanger the following benefits have been demonstrated:

• Fuel consumption reductions of over 7% measured as an average over 5 NEDC tests
compared to the standard system configuration.
• Significant reductions in exhaust emissions, mainly CO and NOx have been achieved
• Significantly higher oil temperatures during cold start indicate large potential to
reduce engine wear through reduced water condensation in the crankcase
• Fuel consumption reductions of further 3.3% to 4.6% compared to the 7% measured
over the NEDC test can be expected under real world customer usage conditions at
lower ambient temperatures.

Oil temperature measurements and analysis resulted in the idea of a novel system with further potential to reduce fuel consumption. This Oil Viscosity Energy Recovery System (OVER 7™) consists of 3 key features that add significant synergies if combined in a certain way: an oil warm up circuit/bypass, including oil pressure control and Exhaust Gas/Oil Heat Exchanger. The system separates the thermal inertias of the oil in the engine galleries and the oil pan, reduces hydraulic pumping losses, increases the heat transfer from the cylinder head to the oil, and utilises the exhaust heat to reduce oil friction.

The project demonstrated that sensitivity analysis is an important tool for the evaluation of different concepts. Especially for new concepts that include transient heat transfer such a qualitative approach in combination with accurate experiments and measurements can be faster and more efficient in leading to the desired improvements compared to time consuming detailed simulations.

Predicting which season ticket holders will renew and which will not

Research question: A major barrier to retaining existing customers is the difficulty in knowing who is most at risk of leaving (or ‘churning’). Given the strategic and financial importance of season ticket holders (STH) to professional sport teams, this paper examines the effectiveness of a range of variables in identifying the STH who are most likely to churn.
Research methods: A longitudinal field study was undertaken to reflect actual conditions. Survey data of a professional sport team STH were collected prior to the conclusion of the season. Actual renewal data were then tracked from team records the following season. This work was replicated across five professional sport teams from the Australian Football League, with renewal predictions made and tracked for over 10,000 STH.
Results and findings: The results suggest that the ‘Juster’ Scale – a simple, one-item purchase probability measure – is an effective identifier of those most at risk of churning, more than 3 months in advance. When combined with ticket utilization and tenure measures, predictive accuracy improves markedly, to the point where these three measures can be used to provide an effective early warning system for managers.
Implications: Whilst there is a tendency to view STH as highly loyal, these data reinforce the importance of actively managing all customers to reduce churn. Despite their commitment, STH do churn, but those most likely to can be predicted by examining their patterns of behaviour in the current season. Efforts to retain STH need to shift their focus from transactional value assessments.

Comparison of advanced waste heat recovery systems with a novel oil heating system

Latest trends in waste heat recovery include systems like Thermo Electric Generation (TEG), Rankine cycle, and active warm up systems. The advantages and disadvantages of different approaches are critically discussed and compared with a novel and effective oil heating system that can deliver between 7% and 12% reductions of CO2 emissions and fuel consumption. The comparison includes the expected CO2 and fuel saving potential related to the legal drive cycle as well as real world driving, effects on regulated exhaust emissions, utilisation of resources, maintenance and service, vehicle performance, comfort, noise, and durability.

A simple-to-use calculator for determining the total solar heat gain of a glazing system

Architects and designers could readily use a quick and easy tool to determine the solar heat gains of their selected glazing systems for particular orientations, tilts and climate data. Speedy results under variable solar angles and degree of irradiance would be welcomed by most. Furthermore, a newly proposed program should utilise the outputs of existing glazing tools and their standard information, such as the use of U-values and Solar Heat Gain Coefficients (SHGC’s) as generated for numerous glazing configurations by the well-known program WINDOW 6.0 (LBNL, 2001). The results of this tool provide interior glass surface temperature and transmitted solar radiation which link into comfort analysis inputs required by the ASHRAE Thermal Comfort Tool –V2 (ASHRAE, 2011). This tool is a simple-to-use calculator providing the total solar heat gain of a glazing system exposed to various angles of solar incidence. Given basic climate (solar) data, as well as the orientation of the glazing under consideration the solar heat gain can be calculated. The calculation incorporates the Solar Heat Gain Coefficient function produced for the glazing system under various angles of solar incidence WINDOW 6.0 (LBNL, 2001). The significance of this work rests in providing an orientation-based heat transfer calculator through an easy-to-use tool (using Microsoft EXCEL) for user inputs of climate and Solar Heat Gain Coefficient (WINDOW-6) data. We address the factors to be considered such as solar position and the incident angles to the horizontal and the window surface, and the fact that the solar heat gain coefficient is a function of the angle of incidence. We also discuss the effect of the diffuse components of radiation from the sky and those from ground surface reflection, which require refinement of the calculation methods. The calculator is implemented in an Excel workbook allowing the user to input a dataset and immediately produce the resulting solar gain. We compare this calculated total solar heat gain with measurements from a test facility described elsewhere in this conference (Luther et.al., 2012).

Heat reflective layered garment system

Heat-reflective layered apparel or footwear constructed from various combinations of layers of materials having selected thermal and moisture transfer properties to provide improved performance characteristics. Within these various combinations, the addition of a very thin heat reflective layer, made with a metallic material such as aluminum, applied using a vacuum plasma vapor deposition method, provides a coating that will reflect infra red heat energy either back to the body or away from the body. This heat reflective coating is so thin that is does not adversely alter the original suppporting fabrics hand feel, drape,weight , strectch or breathability. Various layers manage the body heat of an individual by reflection or thermal retention while also providing moisture wicking and antimicrobial function. Other layers manage thermal isolation from the external temperatures by using materials with very low thermal conductivity in combination with waterproof layers that can also be breathable.

Comparison of advanced waste heat recovery systems with a novel oil heating system

Latest trends in waste heat recovery include systems like Thermo Electric Generation (TEG), Rankine cycle, and active warm up systems. The advantages and disadvantages of different approaches are critically discussed and compared with a novel and effective oil heating system that can deliver between 7% and 12% reductions of CO2 emissions and fuel consumption. The comparison includes the expected CO2 and fuel saving potential related to the legal drive cycle as well as real world driving, effects on regulated exhaust emissions, utilisation of resources, maintenance and service, vehicle performance, comfort, noise, and durability.

Characterization of conducting polymer coated synthetic fabrics for heat generation

Heat generation in fabrics coated with the conductive polymer polypyrrole was investigated. The PET fabrics were coated by chemical synthesis using four different oxidizing agent–dopant combinations. The samples from the four different dopant systems all show an increase in temperature when a fixed voltage is applied to the fabric. The antraquinone-2-sulfonic acid (AQSA) sodium salt doped polypyrrole coating was the most effective in heat generation whereas the sodium perchlorate dopant system was the least effective. The power density per unit area achieved in polypyrrole coated polyester–Lycra® fabric with 0.027 mol/l of AQSA acting as dopant was 430 W/m². The power density per unit area achieved for the sodium perchlorate system, using the same synthesis conditions, was 55 W/m².

Life-cycle energy analysis of building integrated photovoltaic systems (BiPVs) with heat recovery unit

Building integrated photovoltaic (BiPV) systems generate electricity, but also heat, which is typically wasted and also reduces the efficiency of generation. A heat recovery unit can be combined with a BiPV system to take advantage of this waste heat, thus providing cogeneration. Two different photovoltaic (PV) cell types were combined with a heat recovery unit and analysed in terms of their life-cycle energy consumption to determine the energy payback period. A net energy analysis of these PV systems has previously been performed, but recent improvements in the data used for this study allow for a more comprehensive assessment of the combined energy used throughout the entire life-cycle of these systems to be performed. Energy payback periods between 4 and 16.5 years were found, depending on the BiPV system. The energy embodied in PV systems is significant, emphasised here due to the innovative use of national average input–output (I–O) data to fill gaps in traditional life-cycle inventories, i.e. hybrid analysis. These findings provide an insight into the net energy savings that are possible with a well-designed and managed BiPV system.

Local total and radiative heat-transfer coefficients during the heat treatment of a workpiece in a fluidised bed

The heat-transfer coefficients around a workpiece immersed in an electrically heated heat treatment fluidised bed were studied. A suspension probe designed to simulate a workpiece of complex geometry was developed to measure local total and radiative heat-transfer coefficients at a high bed temperature. The probe consisted of an energy-storage region separated by insulation from the fluidised bed, except for the measuring surface, and a multi-thermocouple measurement system. Experiments in the fluidised bed were performed for a fluidising medium of 120-mesh alumina, a wide temperature range of 110–1050 °C and a fluidising number range of 1.18–4.24. It was found that the workpiece surface temperature has a more significant effect on heat transfer than the bed temperature. The total heat-transfer coefficient at the upper surface of the workpiece sharply decreased at the start of heating, and then steadily increased as heating progressed, while a sharp decrease became a rapid increase and then a slow increase for the radiative heat-transfer coefficient. A great difference in the heat-transfer coefficients around the workpiece was observed.

A medium-temperature solar thermal power system and its efficiency optimisation

This paper firstly expounds that the reheat-regenerative Rankine power cycle is a suitable cycle for the parabolic trough collector, a popular kind of collector in the power industry. In a thermal power cycle, the higher the temperature at which heat is supplied, the higher the efficiency of the cycle. On the other hand, for a given kind of collector at the same exiting temperature, the higher the temperature of the fluid entering the collector, the lower the efficiency of the collector. With the same exiting temperature of the solar field and the same temperature differences at the hottest end of the superheater/reheater and at the pinch points in the heat exchangers (e.g., the boiler) in the cycle, the efficiencies of the system are subject to the temperature of the fluid entering the collector or the saturation temperature at the boiler. This paper also investigates the optimal thermal and exergetic efficiencies for the combined system of the power cycle and collector. To make most advantage of the collector, the exiting fluid is supposed to be at the maximum temperature the collector can harvest. Hence, the thermal and exergetic efficiencies of the system are related to the saturation temperature at the boiler here.

Integrated optimization system for high pressure die casting processes

High pressure die casting (HPDC) is a versatile process for producing engineered metal parts by forcing molten metal under high pressure into reusable steel dies. However there are a large number of attributes involved which contribute to the complexity of the process. A novel integrated approach is developed to optimize the high pressure die casting processes. The die temperature profiles will be studied with infrared thermograph technology and the internal cooling system will be optimized to provide even cooling to the components and the die. The heat stored in the die and the components is studied with image processing. Based on the geometrical profile of the components, cooling channels can be redesigned to improve the cooling efficiency while the cooling time is reduced. This will not only significantly improve the quality of the castings but also improve the productivity of the process.