Integrating Latent Load into the Cooling Degree Days Concept for Current and Future Weather Projections

Rising temperatures, increase in population, and dense urban morphology have resulted in increased cooling energy demands. The conventional degree-days method to calculate cooling energy demand considers only the sensible heat load of air and neglects the latent component. This study aims to estimate the cooling degree days based on the heat index (by considering both the sensible and latent loads) for the current and future years (2050 and 2080). Further, the ventilation load index for each of these cities has been established to unlock the impact of ventilation on the building’s total energy consumption for current and future years. The results show that heat index- based degree days have a stronger relationship with the buildings’ cooling energy consumption and, therefore, can predict the cooling energy demand of buildings with 20% higher accuracy than conventional temperature-based degree days. Analysis shows that cooling degree-days and frequency of temperature above the comfort range continue to increase in Pakistan, highlighting increased degree-days in the range from 11.0 to 41.6% by 2050 and from 28.4 to 126.5% by 2080. Prompt actions are essential to enhance the resilience of Pakistan’s national grid to meet these future cooling energy demands

Energy-related environmental and economic performance analysis of two different types of electrically heated student residence halls

Student residence halls occupy 26% of the total area of a typical university campus in the UK and are directly responsible for 24% of university’s annual CO2 emissions. Based on five years measured data, this paper aims to investigate the energy-related environmental and economic performance of electrically heated residence halls in which space heating is provided by two different types of electric heaters, that is, panel heater (PHT) and storage heater (SHT). Secondly, using statistical and machine learning methods, the paper attempts to investigate the relationship between daily electricity consumption and five factors (ambient temperature, solar radiation, relative humidity, wind speed and type of day). Data analysis revealed that electricity consumption of both halls is mainly driven by ambient temperature only, whereas SHT residence has 39% higher annual electricity bill and emits 70% higher CO2 emissions on a per square metre basis compared to the PHT residence hall

Development of a Combined Heat and Power sizing model for higher education buildings in the United Kingdom

© 2018 Elsevier B.V. The four Higher Education Funding Councils in the United Kingdom want all universities to reduce CO2 emissions by 34% by 2020 compared to a 2005 base. Universities that have installed Combined Heat and Power (CHP) technology are making good moves towards achieving their CO2 reduction target. For a CHP project to be successful, a detailed technical, economic and environmental assessment is required. Generally, this assessment is carried out using a computer-based model. Currently, available CHP models have limitations in terms of flexibility, accuracy, reliability and complexity and their use could result in an undersized or oversized CHP scheme that could lead to a complete failure of the project. Therefore, there is an urgent need for a robust and user-friendly model, which integrates multiple features that are missing in the currently available models. This paper presents the development of a spreadsheet based CHP sizing model for a single or multiple university buildings. The major strengths of the model are its simplicity, flexibility of data entry, selection of multiple electrical and thermal demands, an in-built real database for a range of CHP sizes, multiple control strategies, multiple investment routes and their life cycle cash flow analysis, and the potential for detailed sensitivity analysis of payback period using the Monto Carlo Simulation technique. The model, which we call the London South Bank University (LSBU) CHP model, has been tested with three other CHP models for different control modes for the same building and the comparisons are discussed

Techno, Economic and Environmental Assessment of a Combined Heat and Power (CHP) System—A Case Study for a University Campus

Universities in the United Kingdom that have installed Combined Heat and Power (CHP) technology are making good moves towards achieving their CO2 reduction targets. However, CHP may not always be an economical option for a university campus due to numerous factors. Identification of such factors is highly important before making an investment decision. A detailed technical, economic, and environmental feasibility of CHP is, therefore, indispensable. This study aims to undertake a detailed assessment of CHP for a typical university campus and attempts to highlight the significance of such factors. Necessary data and information were collected through site visits, whereas the CHP sizing was performed using the London South Bank University (LSBU) CHP model. The results suggest that there is a strong opportunity of installing a 230 kW CHP that will offset grid electricity and boilers thermal supply by 47% and 75%, respectively, and will generate financial and environmental yearly savings of £51k and 395 t/CO2, respectively. A wider spark gap decreases the payback period of the project and vice versa. The capital cost of the project could affect the project’s economics due to factors, such as unavailability of space for CHP, complex existing infrastructure, and unavailability of a gas connection

The Significance of a Building’s Energy Consumption Profiles for the Optimum Sizing of a Combined Heat and Power (CHP) System—A Case Study for a Student Residence Hall

University buildings, such as student residence halls with year-round consistent energy demands, offer strong opportunities for Combined Heat and Power (CHP) systems. The economic and environmental feasibility of a CHP project is strongly linked with its optimum sizing. This study aims to undertake such an assessment for a CHP system for a student residence hall located in London, the United Kingdom (UK). The study also aims to undertake a sensitivity analysis to investigate the effect of different parameters on the project’s economics. Necessary data are collected via interviews with the University’s Energy Manager. Modeling of the CHP system is performed using the London South Bank University (LSBU, London, the UK) CHP model. Results demonstrate that optimum sizing of CHP is crucial for achieving higher economic and environmental benefits and strongly depends on the authenticity of the energy consumption data, based on which the CHP is being sized. Use of incorrect energy data could result in an undersized or oversized CHP system, where an oversized system will result in higher negative results compared to an undersized system. Finally, Monto Carlo statistical analysis shows that electricity price is the significant factor that could affect the project’s economics. With an increasing spark gap, the payback period decreases, and vice versa

Numerical Performance Investigation of Parabolic Dish Solar-Assisted Cogeneration Plant Using Different Heat Transfer Fluids

Parabolic dish solar collectors gain higher solar to thermal conversion efficiency due to their maximum concentration ratio. The present research focuses by integrating the parabolic dish solar collector to the steam cycle producing power and rate of process heating. Pressurized water, therminol VP1, and supercritical carbon dioxide are the examined working fluids in the parabolic dish solar collector. The aim of the current research is to observe the optimal operating conditions for each heat transfer fluid by varying inlet temperature and flow rate of the working fluid in the parabolic dish solar collector, and combination of these parameters is predicted to lead to the maximum energy and exergy efficiencies of the collector. The operating parameters are varied to investigate the overall system efficiencies, work output, and process heating rate. Findings of the study declare that water is an efficient heat transfer fluid at low temperature levels, whereas therminol VP1 is effective for a higher temperature range. The integrated system efficiencies are higher at maximum flow rates and low inlet temperatures. The efficiency map of solar collector is located at the end of study, and it shows that maximum exergy efficiency gains at inlet temperature of 750 K and it is observed to be 37.75%

Energy and environmental performance of a higher education sector – a case study in the United Kingdom

In 2010, the UK’s Higher Education Sector set a carbon reduction target of 43%. This study aims to evaluate the performance of this Sector for the period before and after the implementation of its carbon reduction target. Dataset available from the Higher Education Statistics Agency has been extensively used in this study. Significant factors driving the sector’s energy consumption have been identified. Energy performance indicators have been established. The increasing role of green technologies in the sector’s energy mix has been unlocked. The sector’s energy and carbon performance have been additionally analysed by critically analysing the data collected from the display energy certificates. In the end, the impact of Brexit on the sector’s academic and environmental targets has been discussed

Unlocking Household Electricity Consumption in Pakistan

In Pakistan, data for household electricity consumption are available in the form of monthly electricity bills only, and, therefore, are not helpful in establishing appliance-wise consumption. Further, it does not help in establishing the relationship among the household electricity consumption and various driving factors. This study aimed to unlock the household electricity consumption in Pakistan by analyzing electricity bills and investigating the impact of various socioeconomic, demographic, and dwelling parameters and usage of different appliances. The methodology adopted in this study was survey-based data collection of the residential sector. For this purpose, data were collected from 523 dwellings through surveys and interviews in Mirpur city. The results of the data analysis revealed that the average household electricity consumption is 2469 kWh/year with an average family size of seven and an average floor area of 78.91 m2. Based on possession of various appliances, the households were categorized into four types and their consumption patterns were established and compared. Air Conditioned (AC) houses consume 44% more electricity compared to the non-AC houses, whereas an Uninterrupted Power Supply (UPS) consumes electricity equivalent to an AC. The research findings are useful for policy makers and building designers and are discussed in the conclusion section

Small-Sized Parabolic Trough Collector System for Solar Dehumidification Application: Design, Development, and Potential Assessment

The current study presents a numerical and real-time performance analysis of a parabolic trough collector (PTC) system designed for solar air-conditioning applications. Initially, a thermodynamic model of PTC is developed using engineering equation solver (EES) having a capacity of around 3 kW. Then, an experimental PTC system setup is established with a concentration ratio of 9.93 using evacuated tube receivers. The experimental study is conducted under the climate of Taxila, Pakistan in accordance with ASHRAE 93-1986 standard. Furthermore, PTC system is integrated with a solid desiccant dehumidifier (SDD) to study the effect of various operating parameters such as direct solar radiation and inlet fluid temperature and its impact on dehumidification share. The experimental maximum temperature gain is around 5.2°C, with the peak efficiency of 62% on a sunny day. Similarly, maximum thermal energy gain on sunny and cloudy days is 3.07 kW and 2.33 kW, respectively. Afterwards, same comprehensive EES model of PTC with some modifications is used for annual transient analysis in TRNSYS for five different climates of Pakistan. Quetta revealed peak solar insolation of 656 W/m2 and peak thermal energy 1139 MJ with 46% efficiency. The comparison shows good agreement between simulated and experimental results with root mean square error of around 9%