Description of the neighbourhood
The Manchester Town Hall Extension (THX) is an important facility for the city’s administration. It is a narrow plan steel and concrete framed building 8 floors completed in 1938. It has undergone a major refurbishment during the period 2011-13 to bring it up to a modern office standard and is now being gradually re-occupied. As a heritage building the options for the improvement to the thermal performance of the fabric are limited, (the building is grade II listed 1clad in sandstone with steep pitched lead roof). The appearance of the exterior and much of the interior had to be maintained which, with the narrow frame section of the windows precluded application of internal or external insulation. Instead, to address the CO2 abatement target, the design strategy has been to focus on increasing the efficiency of the new heating and cooling systems and in their control.
The THX is part of the Manchester Town Hall Complex (THC) which has been equipped with a “bespoke” heating and cooling system. This consists of a gas boiler installation to supply the main heating load as well as a CHP installation for electrical supply. Waste heat from the CHP is utilised efficiently controlled by the Building Energy Management System (BEMs) as explained below. Two 358 kWh CHP engines supply all the electricity needs of THC – 1MVa load. During heating periods (daytime) waste heat from CHP engines (330kW) feed into + preheat three 1062kW gas boilers for main LTHW system. Three 500l LTHW buffer vessels on HW supply to floor zones via ultrasonic heat meters. Radiators with TRV are mounted under windows in each floor zone. Connected heating load = 3MW. Main office floors are naturally ventilated and this supports summer cooling (narrow plan floor plate). Overnight unused/waste heat from CHP is used to feed one 200kw absorption chiller which charges a chiller store of seven 7000l chilled water storage vessels which supports base cooling load for most of the year (ICT area + some conference facilities). One 486Kw electric chiller supports additional peak summer cooling load - max 600kW. A heat exchanger controls waste heat flow from CHP units to boilers (330kw max) and absorption chiller (230Kw max). In low occupancy periods e.g. overnight one of the two CHP units shuts down (50% turndown ratio).
The use cases will look at the energy use of the whole building as well as the staff occupants/users of office floor zones along with technical measures to manage internal lighting.
They all have different elements of character and so the square, as a point of interface, has particular significance. The square and the buildings around it are now at the northern end of the City’s “Corridor Partnership” regeneration area and the regeneration strategy for this area is a key strategic priority for the City Council and the partners and stakeholders in the partnership, focusing in particular on employment, innovation and sustainability.
Manchester’s Town Hall Extension is a building of national significance, among the best examples of architecture of its period and part of a civic complex of world class stature. Manchester City Council is working to transform the working environment within the building and to create welcoming, inspirational and active public spaces, including a ‘one stop’ Customer Service Centre, which will transform the way in which the City Council’s services are delivered to customers.
Buildings involved in the scenario
The Town Hall complex (THC) is part of the Corridor Low Carbon Economic Area initiative, which is an area of 4 sq. km. centred on the two main universities, the University of Manchester and Manchester Metropolitan University together with the City's main teaching hospital complex, Manchester Science Park and a diverse set of small neighborhoods ranging from high value apartments, to student and key worker accommodation to social housing. The Town Hall complex is at the northern tip of the Corridor area and is comprised of two core buildings, the Town Hall Extension (the main administrative building) and the Central Library. The immediate neighborhood, known as the “Civic Quarter” is a mix of office buildings and hotels including a new office complex, One St. Peter’s Square, opposite the Central Library, due to open in 2014 with 268,000 sq. ft. (25,000 sq.m.) of Grade A office space and the historic Midland (Railway) Hotel opened in 1903 which, like the Town Hall Extension and the Central Library, is a Grade II* listed building.
The scenario to be tested will try to address how to use smart energy management systems to ensure a 29% reduction in CO2 across the main complex and to identify ways that the local neighborhood could share energy systems across buildings, through a Civic Quarter Heat Network (CQHN).
Impact and expected results
Critical to the success of the project is how to use the information collected across the intelligent devices and present them to various stakeholders to positively influence behavioural change and the associated more efficient use of the Town Hall Complex Itself and then as a core facility within the CQHN.
Therefore the methodology for the approach to the project is as follows:
- Identification of the monitoring and data collection points across the complex.
- Specification, procurement and implementation of the monitoring / measuring equipment.
- Integration approach to interoperability across the different platforms and the integration onto the IP Network.
- Presentation of real-time information to relevant stakeholders in order to react to changing demands and positively impact on end user behaviour.
- Post occupancy monitoring to ensure data accuracy and that the information is driving behavioural change.
- Using the data to inform the development of the CQHN proposal thus enabling the Heat Network to be developed more rapidly and more efficiently.
Scenario and use cases involved
Two key scenarios will be addressed in Manchester pilot case:
- Scenario at neigbourhood level: Manchester Civic Quarter Heat Network (MCQHN) Use Case will try to address questions like
- Heat energy consumed per square meter of floor space/annum (kWh/m2/year).
- Electrical energy consumed per square meter of floor space/annum (kWh/m2/year)
- Energy demand for commercial buildings (kWh/m2/year)
- Heat transfers ( MJ per year)
- Cost of heat supply (£/MJ)
- CO2 emissions from the whole network (Kg per year)
- CO2 emissions from the electrical consumption/supply in the network (Kg/m2/year)
- CO2 emissions from the overall heat supply in the network (Kg/m2/year)
- CO2 savings per square meter (Kg/m2/year)
- Local economic effects of the heat network (£s/capita)
- Socioeconomic effects of the heat network (jobs/year)
Figure. Buildings to be included in the MCQHN and proposed network routes
- Scenario at building level: Manchester Town Hall Extension (THX) Use Case will try to address questions like
- Energy consumed /square meter of floor space
- Energy consumed /occupant or employee
- Energy consumed/ occupant or employee/ square meter of floor space
- Energy consumed/occupant or employee/daily travel to work
Figure. Floor zones in Town Hall Extension - heating
Main actors and stakeholders involved
The main stakeholders and actors involved include:
- City energy manager: Manchester City Council at policy level; both elected members and senior management
- Facility energy manager: Manchester City Council as an employer: staff
- Users of the facilities: Residents, businesses and visitors
- Utility: Energy/utility suppliers, e.g. Electricity North West (ENW)