CONURBANT - IEE/10/380/SI An inclusive peer-to-peer approach to involve EU CONURBations and wide areas in participating to the CovenANT of Mayors New opportunities for buildings efficiency

CONURBANT - IEE/10/380/SI Why buildings need heat and how they lose it? To keep warm the air inside the building (usually at 20 °C) it’s necessary an amount of energy from 30 kWh/m2 year (the best efficiency actually available) to 250 kWh/m2year (the worst one). Obviously, it depend from external temperature and solar radiation

CONURBANT - IEE/10/380/SI Building Energy Efficiency: some principles Heat Production Combustion Heat loss Heat Distribution Heat loss Insulation HeatEmission Temperature differential Delta T Heat regulation Environment temperature From fuel to warm there are four steps of energy transformation … and energy dissipation …

CONURBANT - IEE/10/380/SI Energy saving options – building envelope Heat losses can be reduced with a better wall insulation: Better internal comfort High energy saving + Long payback time Not easy application -

CONURBANT - IEE/10/380/SI Energy saving options – heating plant Improving efficiency of heat generator, regulation and emission Cheap and no invasive intervention High energy saving Short payback time + None -

CONURBANT - IEE/10/380/SI Energy saving options – heating plant Improving efficiency of heat generator, regulation and emission Condensing boiler: with high temperature systems too 5-7% Thermostatic valves: easy and cheap intervention which provide at least 5% of energy saving Regulation: temperature control for each room Emission: low temperature emission system

CONURBANT - IEE/10/380/SI How to obtain data: energy audit INTRODUCTION The objective of an energy audit is to identify economical energy/cost saving measures that do not adversely affect environmental comfort standard

CONURBANT - IEE/10/380/SI Scope of an energy audit Energy audit is a needed step in implementation of any detailed and sizable energy efficiency project. The major impetus behind an energy audit is that the analysis of energy consumption and identification of potential conservation measures.

CONURBANT - IEE/10/380/SI There are two basic types of audits … 1.walk-through audit: with the aim to identify potential energy saving measure 2.investment grade audit. Investment grade audit is also called feasibility audit. It may be a comprehensive audit that is intended to identify all energy efficiency opportunities or a more targeted audit which focuses on a specific piece of equipment or process, e.g. lighting, a boiler..

CONURBANT - IEE/10/380/SI First step of a walk through audit … a meeting should be held with the appropriate personnel The purpose is to determine which of the systems, technologies, and equipment listed below actually applied and where focus your attention during the walk- through audit.

CONURBANT - IEE/10/380/SI Second step of a walk through audit … go through the checklist of questions in a guide that pertain to the building. good opportunity to discuss any concerns that the personnel may have with implementing the energy saving measures

CONURBANT - IEE/10/380/SI Third step of a walk through audit … tour the building with the appropriate personnel that are familiar with the various areas that you will be auditing. refer to a guide to ensure that you answer any remaining checklist questions. The back of each page can be used to record your observations, such as equipment nameplate data, gage readings, meter readings, and to make notes, such as areas that require further study

CONURBANT - IEE/10/380/SI Investment grade audit Def: IGA is a technical and economic analysis of potential energy saving projects in a facility that: Provides information on current energy consuming equipment operations Identifies technically and economically feasible energy efficiency improvements for existing equipment, and Provides the customer with sufficient information to judge the technical and economic feasibility of the recommended projects.

CONURBANT - IEE/10/380/SI Which data must be collected Heat generator 1.Nominal power 2.Year of contruction 3.Working temperature Inside the building 1.Envelope properties (thickness of the wall, characteristics of the bricks, insulation if present) 1.Walls 2.Floor 3.roofs 2.Windows charachteristics (number of glass sheets, frame, etc…) 3.Tipology of emission systems (radiators, low temperature systems,…) 4.Regulation technology (internal centralized switch, regulation for each rooms, external drill for heating temperature driving) Energy Bills!!

CONURBANT - IEE/10/380/SI Energy saving options – Case studies Käthe Kollwitz School in Aachen (Germany). The school, built in 1951 and extended in 1995, had passed its prime. A comprehensive building refurbishment was seen as the way to improve classroom conditions significantly, while reducing energy costs.

CONURBANT - IEE/10/380/SI Energy saving options – Case studies

CONURBANT - IEE/10/380/SI Energy saving options – Case studies With windows accounting for approximately 67% of the outer surface, the school's facade is generously glazed. The exterior walls consist of a single layer of 36.5 cm and 49 cm bricks, partly implemented as exposed brickwork on the outside, while the inside is plastered. In the radiator niche areas, the walls are only 14 cm thick.

CONURBANT - IEE/10/380/SI Refurbishment concept During refurbishment, the combination of two different facade structures was retained, and interpreted in a modern way. Now, areas with a thermal insulation composite system alternate with facade sections made of hung brick elements. Each has 12 cm-thick insulation. Thermally insulating glazing with frames made of wood and aluminium replaces the original single-pane wooden windows. The roof was insulated with 20 cm-thick cellulose fill. Parts of the cellar walls were insulated on the inside in areas with interior temperatures of 20°C. Partly for construction-related reasons, and partly due to cost benefit considerations, some thermal bridges were also consciously accepted: for example, the base remained uninsulated, and no changes were made to the 4-to-5 cm-thick thermal insulation in the areas with no cellar.

CONURBANT - IEE/10/380/SI Energy concept It was possible to convert the heat supply to remote heating. Already in the first construction stage, the entire building was connected to remote heating based on combined heat and power generation. Heating circuit distributors, pump technology, and the centralised control technology were renewed. The piping network was converted from a single pipe, to a two pipe system. In so doing, it was possible to continue using most of the old pipes. Approximately 40 percent of the ribbed radiators could then be removed due to the reduced heating requirement.

CONURBANT - IEE/10/380/SI Energy concept Ventilation: originally, only the kitchens were equipped with a ventilation system. During refurbishment, ventilation systems were installed in all classrooms, whereby the system, control method, and heat recovery differ between the various construction stages. This now enables a comparison of the different systems.

CONURBANT - IEE/10/380/SI Energy concept Lighting: much of the lighting system was out of date. Not able reach the light level required by the German industry standard DIN Solution: mirror louvres with electronic dimmable ballasts, most of which are controlled in a daylight dependant manner.

CONURBANT - IEE/10/380/SI Performance In total, the refurbishment lowered the end energy requirement for room heating, water heating, and ventilation by 65%. Measurements taken during short periods in several classrooms showed CO2 concentrations of up to 5,000 ppm where only window ventilation was used. Where mechanical ventilation was used, at just 16-17m³/h per person, in conjunction with quick ventilation via all windows during breaks, CO2 content of 1,500 ppm (the DIN threshold value) was never exceeded. Construction costs and profitability The refurbishment costs amounted to approximately 2.8 million euros.

CONURBANT - IEE/10/380/SI Key Energy data

CONURBANT - IEE/10/380/SI Economics Refurbishment costs in €/m2 Refurbishment costs (over all)316 Exterior wall44 Windows and doors87 Building services equipment83 Planning costs62 Other building costs16

CONURBANT - IEE/10/380/SI Romano Selva Sogesca srl