Domestic Thermal Energy Storage: A study of the present and future benefits and impacts

Joynal Abedin, Loughborough

Introduction

Reducing our dependence on fossil fuel and increasing the uptake of Renewable Energy Technology (RET) will lead to an energy system with a diverse energy generation mix and greater electrification of the energy demand sectors, including domestic heating. The result will be low power quality due to multiple RET aggregation, large daily peak to off-peak electricity demand variation, large variability in electricity supply due to intermittency in renewable generation, and increased use of electricity for heating leading to a strong seasonal demand variation (Figure 1).

FIgure 1. Half hourly heat and electricity demand profile.
Domestic scale Thermal Energy Storage (TES) has the capability to address these problems by;

1) acting as source or store depending on the availability of energy from the renewables, and 2) by shift the heating loads from peak hours to off-peak hours, thus aiding grid load balancing.

The domestic building sector, as the second largest consumer of energy in the UK (figure 2), and the largest consumer of energy for heating (figure 3), provides us with great opportunity to apply TESe, and help overcome some of the challenges of a future energy system.

Figure 2. Final energy demand by sector in 2009 (source ECUK)

At the household level under the current arrangements, households with on-site micro-generation systems, especially PV, export over 60% of the energy to the grid at a price of ~3p/kWh, and buy it back when the need arises, at cost of approximately 13p/kWh, therefore incurring a ‘loss’ of ~10p/kWh. This could be described as an ineffective use of a valuable resource. A combination of demand side management and short-term TES could encourage greater on-site use of the locally generated energy for heating (water and space), benefitting both the supply and demand side stakeholders. Further, the benefit could be considerable given the size of the UK domestic building sector, and that water and space heating account for almost 80% of the domestic energy consumption (figure 3). Also, households could further benefit financially by exploiting varying energy price tariffs which may be available from the future smart electricity grid.

Figure 3. Final energy consumption in the domestic sector by use type in 2009 (source: ECUK)

In summary, successful implementation of short-term TES and demand side management techniques could provide better grid load balancing options, contribute towards the UK renewable and CO2 emission targets and provide financial benefit for the households. Barriers to successful implementation of the techniques include:

Technical feasibility and effectiveness of such systems
Compatibility with existing energy generation and transmission infrastructure
Short & long term cost implications
Installation & maintenance issues
Embodied carbon content against carbon emission saved over system life cycle
Acceptability of such systems by the consumers
Legislative and policy issues
This PhD will explore the feasibility of domestic scale TES as a potential solution to the problems highlighted above, through dynamic modelling and simulation of building energy demand, demand side management and their present and future benefits and trade-offs.

Aim

“To investigate the potential of thermal energy storage in domestic buildings and the associated present and future benefits.”

Objectives

To review the role of TES in the UK energy system and its relevance to the national energy policy.
To review the methods and technologies available for TES in the domestic building sector.
To investigate the demand for thermal energy in domestic buildings, and the potential of temporal shifting of the demand through the use of TES and Demand Side Management (DSM).
To develop a building model to simulate the effects of heat storage in UK homes.
To simulate the energy demand and storage potential for a UK home type and analyse the benefits, and trade-offs, of different storage solutions.
To identify and recommend domestic TES strategy to maximise sustainability and resilience of the UK energy system.

Student(s)
Joynal Abedin
Supervisor(s)
Philip Eames
Steven Firth

Conference poster

Lo-Lo Summer Event – 2012

Poster & presentation oulining the reseach, findings to date and the future research plan.

LoLo Annual Colloquium 2012

Poster presenting the reaseach progress and results to date.

MEGS Annual Christmas Conference

Poster presented a thermal storage modelling case study investigating the potential of heat energy demand shifting in time, in a two bedroom detached house, with typical occupancy and building operational conditions

Presentation

Modelling and Measurement mini-conference, Loughborough University.

Presented the finding (so far) of a case study simulating the heat demand shifting potential within a two bedromm detatched household with typical occupancy and operational characteristics.

Report (progress/mini project/consultation reports)

Domestic Thermal Energy Storage: A study of the present and future benefits and impacts .

First year report presenting the literature review findings, and a building thermal modelling case study results and research plan for the second and third year.