The Leiden City Hall is a historic building, stone built in 1600, partly rebuilt in 1932 that provides public services to the citizens, hosts offices and meeting rooms.

The building had an energy audit performed in 2007 that resulted in a number of technical solutions for energy efficiency that have been gradually adopted. Due to its monument status, rigorous physical changes to the building are not allowed. Changing users behaviour would be a cost-effective means to achieve  energy savings.

The objective of the Pilot is to test the hypothesis that behavioral change occurs when real time information about energy use is available. We are using 12 rooms equipped with sensors for electricity use and heating energy consumption. Rooms have different numbers of employees and different layouts.

The main objective is to define a best practice case, so the results can be used in  all City buildings to reduce energy consumption in a cost-effective manner.

Scope

The Save Energy Leiden Pilot is one of five pilots of the EU project “Save Energy”, CIP-ICT-PSP-2008-2, aimed at demonstrating the use of ICT for energy savings in public buildings and spaces through behavioural changes. Savings can be attained on the use of electricity (lighting, computers, appliances), heating and cooling. We will test the hypothesis that the energy behaviour of employees can be changed by providing them with current information about the energy used at their desk and in their room. We will also obtain an indication of the amount of energy that can be saved by this approach.

The equipment that is used is commercially available from Plugwise and Sensite. System integration, local data logging, user presentation and integration with the Save Energy infrastructure is provided by AnyWi Technologies B.V.

Objectives

The pilot will provide information on energy use in a limited number of offices in Leyden City Hall during a period of about a year and the effect of providing feedback to the participating employees. An indication will be obtained about the cost effectiveness of the method and the energy savings that can be obtained.

Approach

The Leiden Pilot is carried out in twelve office rooms of the Leiden City Hall. These rooms vary in size, location, equipment, number of desks/persons and the type of activity. Employees in the pilot rooms get information about their ‘real time’ energy use. Originallly we planned to have reference rooms where the employees would not get any information about their energy use, to obtain compartive data and to be able to compensate for environmental factors like varying day light and outside temperature. However from base line measurements it became apparent that variations in personal behaviour are much more significant than changes in external conditions. We have therefore changed the experimental design and make comparisons on a historical, time-line basis. This way we can test the hypothesis that providing information can change personal energy behaviour.

The light in the rooms can be controlled by two (sometimes four) switches both for two sets of fluorescent tubes at the same time. Rooms have venetian blinds that can be opened/closed manually.

The rooms have two windows that can be opened or closed by the employees and two (hot water) radiators for heating that the employees can adjust themselves. Most rooms have two radiators. One of those radiators has a thermostatic control valve, the other one has a manual valve.

We measure both the electricity usage and heating required in each room.

• Personal electricity use per desk, e.g. by computers, screens, desk lamps

• Electricity use per appliance in a room, e.g. by lighting and other room-specific devices like coffee machines or printers.

• Heating energy supplied to the room by each hot water radiator, as estimated from the radiator surface temperature and room temperature.

Employees can influence the energy consumption by:

• switching lights or equipment on/off

• opening/closing the manual radiator control valve

• changing the set point of the thermostatic valve

• opening/closing windows

• opening/closing door(s)

• adjust the venetian blinds

During the pilot we may decide, in consultation with the employees, to place extra sensors to see if extra information might help the user to save more energy. It is for example possible to measure whether a window is opened or closed using an extra sensor or a panel for easy, remote control of appliances may be provided.

Technical Solution

We have installed sensors for the desks (computer screen, computer, miscellaneous), lighting (separate for each appliance) and temperatures (each radiator, air outlet). If a room has some special equipment like a private coffee machine, then an extra sensor has been added to this appliance. We use sensors of the company Plugwise of Sassenheim for the electricity measurements and Sensite temperature sensors (LogiSphere BN215 for room temperature and ST208 for radiator surface temperature). The data that is measured by the sensors is collected by Plugwise concentrators and Sensite HBL100 Wireless Network Controllers that can communicate with an AnyWi router using an open protocol.

TheAnyWi router connects via Internet to the SAVE ENERGY infrastructure. This infrastructure consists of a Middleware Layer, where the Business Logic is applied to the measured data and several clients as the Serious Game, Portal or ProcessVision that use the data from the pilot.

The data is processed and presented to the users. In addition a direct simple feedback to the users may be provided on their pc.

installation of electricity sensors

Installation of temperature sensors