Methodology

CO2 emissions, like primary energy, is a common unit, which can be applied to different forms of delivered energy, e.g. gas, oil, electricity. There is also CO2 emissions associated with the energy needed for the production of building materials and the construction of the building on site, often referred to as embodied CO2. Recently, attention has been focussed on the emissions associated with demolition, which in some cases can be considerable, as well as causing other environmental impacts due to toxicity and pollution. An assessment of all of these components is referred to as life-cycle costing, a term borrowed from financial analysis, or sometimes “cradle to grave” analysis.It is interesting because buildings that may have low emissions in use may require a large “investment” of CO2 in the production of their materials and their construction (or refurbishment). For example, the installation of photovoltaic panels will reduce net electricity consumption during their lifetime, but due to relatively high energy costs in manufacture, would not recover this if installed in poor operating conditions. Though not a problem in the case of photo-voltaics, some low-emission technologies, notably nuclear power plants, have very high emissions associated with decommissioning and demolition.

This work package will apply a CO2 life-cycle analysis to the refurbishment projects. An existing method, available as the software application ENVEST, developed by the Building Research Establishment, UK, has been identified. Although not specifically aimed at refurbishment, the software’s authors are keen to apply it to such projects and make the required additions or modifications. These are likely to be additions to the database relating to the embodied energy of historic materials, and the emissions associated with demolition. The method must be sensitive to the following:

1. Energy for manufacture of materials.

2. Energy for transportation to site.

3. Energy of construction (including disposal of waste).

4. Energy in use i.e. heating, cooling and lighting etc.

5. Energy associated with maintenance.

6. Energy for demolition and disposal of waste.

The items above will not be direct inputs but must be evaluated from user inputs within the procedure. For example item 1. Embodied energy in materials, will be evaluated from quantities and from reference to a database. Item 3. Energy of construction must have an input available to the user such as m2 of building surface of certain type, rather than the number, power and running hours of machines on site etc..

The Environmental evaluation will cover the following areas:

CO2 Building Stock Budgeting

Objectives:

Methodology

The CO2 life-cycle analysis procedure will in the first instance be applied to the case study buildings. The procedure will then be extended to apply to populations of buildings. Two situations will be covered – (a) where the building stock is large and will need to be described in generic terms and (b) small enough for each building to be considered separately.

In case (a) a dynamic population model will be derived – by determining values for parameters such as present stock (by use and age categories), and future demolition, refurbishment, and new-build rates, future building stock compositions will be able to be predicted. Standard values of annual and life-cycle emissions would be derived for the building categories in the population model on a per m2 basis. By integrating over different time frames, a spreadsheet incorporating the dynamic population model and the standard values, will permit owners to model the evolution of their total CO2 emissions. Failure to meet the Kyoto target might indicate to the owner, for example, that the increase of emissions associated with an expansion of the building stock by new building, would need to be compensated by a sufficient rate of energy refurbishment to the existing stock.

In case (b) the dynamic population model will be replaced by a list of actual buildings, together with their category and current status. The yearly dynamic will be described by an array of future lists, one for each year, where anticipated changes of status – e.g. demolition or refurbishment, and new entries to the list, will be recorded manually. By editing the data in the list, and re-running the model, an instant feedback of the impact on CO2 emissions can be obtained. Alterations can be saved as sets of yearly lists, representing different scenarios – e.g. high growth, low growth, high refurbishment rate, static etc, and tested. The technique will be applied to the building stocks of the owners of the five participant buildings, and various refurbishment scenarios tested.

Further details on the methodology can be found in the following document:
CO2 Building Stock Budgeting

Monitoring definition and management

Objectives:

A fundamental task of the project is to carry out monitoring of the completed building. This is a basic requirement; to ascertain if the project is achieving the anticipated performance. As well as energy performance, other aspects will be monitored such as, for example, the impact of the applied measures on comfort, problems with ageing or weathering of materials, failure of control equipment etc. Considerable expertise already exists within the EU and this will be utilised as much as possible and disseminated via the Forums.Two kinds of technical monitoring have been identified – base level monitoring, which will normally be accomplished by the BEMS, and short term exploratory monitoring which will involve temporary monitoring equipment and sometimes more intervention and disturbance. Base level monitoringElectrical consumption by circuit (configured to separate lighting zones and other electrical uses (e.g. computers etc),Hourly profile of electrical circuits,Heat flows by zone. Monitoring will be conducted on three levels:

Base Level Monitoring:

Short Term Explanatory Monitoring:

Post OccupancY Evaluation Monitoring:

A third kind of monitoring will by to study the response of the occupants. This is often referred to as Post Occupancy Evaluation (POE). The information is gathered by questionnaire and the responses processed by statistical analysis. This activity will be given high importance, since any success in energy saving must be balanced against the provision of satisfactory levels of comfort. Furthermore, in some cases refurbishment actions may only improve comfort and have no direct energy pay-off (e.g. improved summer comfort in a non air-conditioned building).There are a number of studies on POEs and suggested formats for the questionnaires in the literature, and these will be consulted before a decision on the final content is made. The precise wording, and their translation into the local language have been found to be critical, and this aspect will receive special attention.