Scope of Research

In order to decrease fossil fuel consumption used for heating and also to reduce CO2 emissions in

university buildings, an accurate modelling method, benchmarks, and renewable energy technologies must be developed further to convert current campuses into green campuses. University buildings have enormous potential to mitigate global warming by reduction of fossil energy consumption. The scope of this PhD study is to reduce fossil thermal energy in a group of buildings located on a university campus (UC) by improving the thermal benchmark and developing a detailed model of thermal energy demand at the campus level. A rich dataset was developed during the PhD research process and using this dataset, the monthly thermal energy models and benchmarks were created to produce the heat maps (HM) at the campus level. Then, ultimately HMs were used to implement the concept of sharing surplus thermal energy between campus buildings.

1.2.1. Thesis Objectives

The objectives of the study are based on the gaps in the field. The thesis main objectives are as follows:

• To discover the accuracy of CIBSE TM46 UC thermal benchmark for Dublin universities

• To improve the UC benchmark reliability for typical college buildings

• To create a new generation of UC thermal benchmarks which are more informative and accurate compared with the current CIBSE UC benchmark

• To understand thermal energy patterns of various building types on a campus. Linking the various thermal patterns to form a larger thermal network demand-surplus model at the campus level

• To develop a new method for managing thermal energy at the campus level

• To assess and validate the advantages of the proposed methods for example revised UC benchmark and monthly benchmarks compared with current annual UC benchmark

• To generate a validated GIS based tool used for smart thermal energy management at the campus level. The tool should link various levels of data and should be useful to match with different sources of energy such as solar and geothermal energy.

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1.2.2. Thesis Limitations

The barriers in front of the current research and its limitations are as follows:

• Access to the DEC dataset of public buildings in Ireland was the main barrier in front of this research. Particularly a limited number of DECs of sport centres, restaurants and general accommodations was obtained during the research were limited. Therefore, the thesis did not generate monthly thermal energy models for these types of buildings.

• The thesis focused on the investigation of thermal energy consumption and did not consider electricity consumption. The thermal and electricity consumption were separated because there are key differences between them in terms of efficiency management, drivers, and consumption patterns [53]. For example, heat (thermal energy) is mainly used for space heating in educational buildings and obviously, it is seasonally dependant. In contrast, electricity consumption depends on the devices and their efficiency and less dependent on the building physics such as building envelope quality and area. In other words, the number of pupils and efficiency of electrical equipment impacts on the electricity energy demand, while heat consumption is highly sensitive to the number and size of classes, theatres, coffee shops/restaurants (activity) and outdoor temperature.

• According to Hong et al. [53] and Kyrö et al. [54], in public buildings such as universities the impact of occupant behaviour on thermal energy consumption is not significant. Therefore, in the monthly thermal energy models the number of pupils/staff was not considered as a driver. Further explanation about the weak impact of occupant behaviour on thermal consumption in public buildings is presented in Chapter 2, Section 2.7.

• The limitation of case studies (four campuses) refers to the lack of actual thermal energy consumption. For example, the data of other universities in Ireland such as the University of Limerick was not available.

1.2.3. Thesis Contributions

The thesis has made six important contributions to the field of thermal energy modelling/benchmarking in university buildings. The first contribution is the revision of current CIBSE TM46 UC benchmark and presentation of an alternative which is more accurate. This process is explained comprehensively in Chapter 4. The revised benchmark reduced the threshold of CIBSE UC benchmark by 110 kWh/m2/yr which is a significant amendment. Using the revised benchmark in the future will radically decrease the fossil thermal consumption of typical college buildings. Considering the large size of typical college buildings (506,000 m2), the impact of

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revised benchmark on reducing of fossil fuel is substantial. Compared with CIBSE TM46, the revised benchmark can reduce the thermal consumption in typical college buildings by 55,643,000 kWh per year.

The second novel contribution of the thesis is to create a new generation of benchmarks which is called monthly thermal energy benchmarks for typical college buildings. These monthly thermal energy benchmarks are introduced as a useful alternative for the current annual-fixed benchmark developed by CIBSE TM46 in 2008.

Third, two new types of monthly thermal energy models based on the mixed activities and DEC values are developed in the thesis. Comparing with the average monthly estimation of CIBSE TM46 UC benchmark, they are more accurate and useful for energy planning and efficiency action plans.

The fourth contribution is the concept of sharing surplus thermal energy between buildings on a campus which is an alternative for thermal energy storage (TES). The concept of sharing surplus thermal energy across a DH system and smarter management of the system using thermal energy maps can also extrapolate into an urban context. For this purpose, a GIS based tool, District Heat Balance (DHB) tool, has been developed.

Accordingly, the thermal energy balance analysis is also new in the field which refers to the balance between potential solar thermal energy and thermal energy demand in each month at an individual building level as well as campus scale. To do so, the monthly heat maps are generated. The maps share more information about heat demand or potential for generating solar thermal energy.

The last contribution of the research is a valuable Energy Building Database (EBD) which shares a lot of information regarding energy and buildings at four case study universities. It includes 120,000 data cells and shares the information of UC as well as Non-UC buildings.

1.2.3. Thesis Outline

Chapter 2 comprises a literature review focusing on seven key areas including; (1) an overview of energy performance and legislations; (2) mixed use building; (3) energy benchmarking and certification; (4) CIBSE TM46; (5) Display Energy Certificate (DEC); (6) DEC-CIBSE, discrepancies & gaps; and (7) Energy mapping.

Chapter 3 involves the approaches undertaken to create and develop a database and it also includes two methods which have been applied to generate the monthly thermal energy benchmarks and

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models. The chapter finally covers the methodology used to set up the District Heat Balance (DHB) tool.

Chapter 4 provides the process of heat assessment in UC buildings resulting in revising the CIBSE UC Benchmark. The chapter explains what is the situation of current CIBSE TM46 UC benchmark by assessing its accuracy.

Chapter 5 explains two methods for generating monthly heat demand benchmarks/models for typical college buildings. In this chapter a new generation of benchmarks as well as thermal modelling are developed and their accuracy and advantages discussed in detail.

Chapter 6 presents the generated heat maps for case study universities. The chapter focused on the analysis of the current heating systems as well as the assessment of fossil thermal consumption at the campus scale. The monthly heat maps for case study campuses are generated. In addition, the efficiency of the current heating system (individual boilers) at TCD campus is assessed as an example. In addition, two thermal systems including DH (District Heating) and individual boilers systems are compared at TCD.

Chapter 7 includes a novel concept of sharing surplus thermal energy between the campus buildings as a useful, cheaper, efficient and applicable alternative of thermal energy storage. The DHB tool is progressed by adding new information to enable the tool to manage and share thermal energy across a UC.

Chapter 8 includes the validation of monthly thermal energy benchmarks and models in a developing campus. Based on the thesis results, the heat demand for campus buildings is estimated at both the building and campus scale. In addition, heat maps are produced and based on the data analysis some methods for smarter thermal energy management and further energy efficiency are proposed.

Chapter 9 contains the detailed conclusions drawn from the research as well as recommendations for future studies. The supplementary documents, secondary data, tables, and maps are presented in Appendices 1 to 3.