Skidmore, Owings & Merrill Foundation Mechanical/Electrical Building Systems Traveling Fellowship FINAL REPORT. José A. Pecchio.

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1 Skidmore, Owings & Merrill Foundation 2001 Mechanical/Electrical Building Systems Traveling Fellowship FINAL REPORT By José A. Pecchio June 2002

2 Table of Contents Introduction...1 A general introduction and statement of intent. Original Plan of Travel...2 A brief explanation of the main features in each building originally intended to be studied. Final Travel Itinerary A timeline graph and a list showing each of the sites and cities that were actually visited and studied. Kreditanstalt für Wiederaufbau (KfW), Berlin, Germany...5 Information gathered during the visit and analysis of the main features of the building. Commerzbank, Frankfurt, Germany...11 Information gathered during the visit and analysis of the main features of the building. Düsseldorf Stadttor (City Gate), Düsseldorf, Germany...17 Information gathered during the visit and analysis of the main features of the building. Institut du Monde Arabe (IMA), Paris, France...23 Information gathered during the visit and analysis of the main features of the building. Personal Viewpoints & Analysis...27 A brief personal viewpoint and analysis of each of the buildings visited. Final Statement...29 A final statement describing how original intentions were fulfilled by travels.

3 Introduction Technological advances in electronics are playing a key role in today s efficient energy utilization. Electronic control systems are now being used more widely because of their precise control, flexibility, compatibility with microcomputers and reliability. Also, advances in electronics have allowed controls to expand and cover a much wider range of applications. Not only are they being used in the traditional energy-using systems in buildings such as HVAC and artificial lighting, but also in other non-traditional building systems such as windows, blinds, and other architectural elements. Moreover, fully integrated and centralized computer digital control systems are now available that are capable of controlling a building as a whole and not just as a number of separate, independent non-interacting systems or areas. During my graduate studies and in my working experience, I have had the opportunity to become familiar with some of the technological advances that are currently being used by the industry in the United States to address the energy efficiency issues of new and/or existing buildings. However, technology keeps advancing at an accelerated pace and numerous innovations and products keep entering the marketplace to address the growing global concerns about energy efficiency and its role in today s economy. It was my goal with this fellowship to learn about what other countries have done in regards to the integration of control systems with mechanical and architectural elements and systems in a building, as well as some of the innovative solutions that have been implemented in an effort to improve the energy efficiency of buildings. Furthermore, it was my expectation to gain valuable knowledge about how other countries are coping right now with the energy efficiency issues and challenges that every country will face sooner or later. 1

4 Original Plan of Travel Kreditanstalt für Wiederaufbau (KfW), Berlin, Germany This is Germany's governmental credit agency for reconstruction, and it is architecturally and technologically a showcase for the future. This facility has blinds that are designed to provide optimal room, task and hallway lighting, providing the most efficient use of daylight. They automatically open and close during the day to either shade or provide more light. A building automation system that is connected to intelligent individual room control devices to maintain temperatures, also controls a number of lighting modules that interact with room occupancy sensors, automatically turning lighting on or off depending on occupancy. The energy from the sun -in combination with the automatic control of the blinds- is even used for temperature control, limiting the need to use mechanical heating or cooling. Düsseldorfer Stadttor (City Gate), Düsseldorf, Germany The ecological design and operation of this building involve a double-shell facade with motorized windows and a new concept called sorption technology, which involves heating and cooling the building using the facade, spring water, and heating/cooling plates. The double-shell facade is used to create a greenhouse effect using window ventilation to condition interior air when the outside air temperature is between 40 and 70 F. When outdoor air temperatures are between 68 and 77 F, the system uses "sorption technology", a combination of exhaust air humidification and heating/cooling plates that continue to provide cool outside air during moderate summer weather. Above 77 F, cooling plates are used to condition the air. The building does not use chlorofluorocarbons at all. The highly distributed and intelligent control architecture and significant integration between systems make this building one of the most interesting energy efficient buildings in the world. Commerzbank, Frankfurt, Germany This building is the tallest building in Europe and one of the first naturally lit and naturally ventilated skyscrapers in the world. This building features a hybrid HVAC concept: a mixture of natural ventilation and mechanical ventilation. If weather is suitable, ventilation and cooling 2

5 systems close down automatically and a light in the control panel indicates that the windows can be opened to naturally ventilate the room. Similarly, if weather is either too hot or too cool for natural air circulation, ventilation and thermal comfort is provided via mechanical systems. Institut du Monde Arabe (IMA), Paris, France This building is the main instrument for the diffusion of Arab culture in France, it is designed to be "a building of dialogue". A dialogue between tradition and modernism established by its transposition of the traditional elements of Arab architecture. This building features photo-cell controlled elements in the main glass facade (a high technology version of the traditional Arab window). This system controls the amount of sunlight that enters the spaces with thousands of photoelectric cells that filter daylight. Inland Revenue Building, Nottingham, UK This building is a good example of a project with great attention for optimal use of the environment: ventilation, solar control, daylighting, etc. Its staircases act as natural ventilation chimneys and it also features a number of other measures taken in relation to solar control, daylight and ventilation. Primary School, Gronge, Norway This school is a very interesting example of hybrid ventilation. The same ventilation system is used for IAQ and summer comfort control. Some of its features are: a water-air heat recovery system between supply and exhaust, the airflow rate at classroom level is controlled by a CO2 sensor which controls the operable windows connected to the ventilation duct. During the heating season, the airflow rate is controlled as a function of the CO2 concentration. Whereas during the cooling season, intensive ventilation is used as part of a strategy for avoiding overheating. 3

6 Final Travel Itinerary Sites and Cities Visited 4 Commerzbank, Frankfurt, Germany 4 Kreditanstalt für Wiederaufbau (KfW), Berlin, Germany 4 Düsseldorf Stadttor (City Gate), Düsseldorf, Germany 4 Institut du Monde Arabe (IMA), Paris, France Final Travel Itinerary /14/02 2/15/02 2/16/02 2/17/02 2/18/02 2/19/02 2/20/02 2/21/02 2/22/02 2/23/02 2/24/02 2/25/02 2/26/02 2/27/02 2/28/02 3/1/02 3/2/02 3/3/02 3/4/02 3/5/02 3/6/02 Dates Commerzbank KfW Stadttor IMA 4

7 Kreditanstalt für Wiederaufbau Berlin, Germany 5

8 The Building Kreditanstalt für Wiederaufbau (KfW) is Germany s governmental credit agency for reconstruction, which was founded after World War II to provide and administer the funds needed to rebuild the Federal Republic of Germany. The building combines historic values and strong ecological values through environmentally friendly construction materials and energy efficient systems and controls that utilize renewable energy sources. The building features innovative lighting and window shade control functions as a part of a Building Automation System. KfW building internal patio facade. The design premise in this building was to create rooms and offices in the building capable of providing an adequate environment and optimal working conditions with as low as possible energy consumption. Of course, maintaining a high degree of flexibility to account for individual preferences of occupants was also a big concern. Automatic Blinds The blinds are designed to provide optimal room, task and hallway lighting while minimizing electric energy consumption. The blinds automatically open and close during the day to either shade or provide more light. The window blinds actually have two parts that automatically open and close according to the time of day, the sensing of light and sensing of the intensity of the light. Automatic blinds with bottom part raised for maximum daylight. 6

9 Mirrored surface of the blinds that reflects sunlight into The upper portion has mirrored reflective surface in the ceiling surfaces that can reflect daylight into a reflective surface in the ceiling. This reflective surface distributes the light evenly into the furthest corners of a room. The most efficient use of daylight is achieved through this function, minimizing the need for task and floor lighting. The upper portion opens when sunlight is needed, and its function is to redirect as much sunlight as possible to the reflective surface in the ceiling. This upper portion is always controlled automatically without user intervention. The bottom part acts as a visor and automatically closes if the light is too intense. The function of this part is to protect against excessive glare in computer screens and excessive direct sunlight into the rooms. This also prevents overheating of the spaces during the summer. This portion can be either automatically or manually controlled. Reflective surface in the ceiling The automated window-blind system works in conjunction with weather stations that have sophisticated sensing technology that tracks information about the intensity of the sun, the level of natural light and other weather conditions such as wind velocity, rain and outdoor air temperature. This information is transmitted through the BAS backbone to the control devices, which then control the slat angle of the blinds to optimize daylight and HVAC performance (the energy of the sun is used for temperature control, limiting the need to use mechanical heating or cooling). Each control device is pre-programmed with the daily position of the sun according to 7

10 the orientation of the window. Natural daylight not only saves energy, but also has positive psychological effects on the occupants. Artificial Lights There are two sources of artificial lights in every room. The primary lights are fixtures located by the windows that can provide additional light (if needed) in a room. These fixtures direct the light to the reflective surface of the ceiling, providing the room with indirect light and without glare. This provides better flexibility and individual control of the light level and quality in each room. Personal preferences can be programmed for these fixtures, which increases user satisfaction. Primary artificial lights that direct light to the reflective surface in the ceiling when there is no sufficient daylight. Indirect artificial lights in a hall There are also additional lighting fixtures integrated in the top of the filing cabinets located in each office. These fixtures are a secondary source of light. Secondary lights embedded in the filing cabinets for additional light. The ultimate effect is a room evenly and adequately lit with little or no glare. Ventilation and Temperature Control When outside conditions are favorable and windows are open, a forced air circulation system located at the entrance of every office is activated that circulates fresh air through the 8

11 room. However, if outside temperatures are extreme, windows are kept closed to avoid excessive cooling/heating loads. The energy from the sun is combined with the automatic control of the blinds to provide temperature control, limiting the need to use mechanical heating or cooling. Operable windows for additional fresh air circulation Room Controls The BAS provides individual comfort control in the facility s 550 rooms, via intelligent individual room control devices. These multifunctional wall-mounted units include three elements: a backlit LCD display, a turn or push knob and four display buttons. A temperature sensor is built into the surface of the device. The LCD display allows a user to view a variety of functions and make numerous adjustments: Room temperature settings can be raised and lowered by 3 degrees Current room temperature is displayed, along optimal values Slat angles are displayed for the upper and lower parts of the window blind Automatic window blind settings can be manually overridden Manual adjustments can be made to the visor in the lower part of the blind Window blinds can be raised or lowered Position of the automated exterior windows is displayed Automated exterior windows can be opened, closed or stopped Task and floor lighting can turned on or off Different menus appear for each type of adjustment, depending on the position of the knob on the front of the display. Additionally, these multifunctional wall devices have four scene buttons. The two upper buttons are for memorizing the two settings that are most commonly used in that room. The third button from the top is for restoring the window blind controls to the automatic mode. 9

12 The fourth button is to switch on or off the floor lighting in the room (if there is no sufficient daylight, artificial lights and/or task lights can be turned on from the control panel for additional light). Each device automatically reverts to the pre-programmed basic setting after a certain period of time when no adjustments are made. The room lighting and individual cubicle lighting controls interact with occupancy sensors, automatically turning lighting on or off depending on occupancy. They can also be operated manually. LCD Display Turn or push knob Glare protection for PC operation Memorized custom settings Automatic mode Floor lights 10

13 Commerzbank Frankfurt, Germany 11

14 The Building With 259 m in height, the Commerzbank headquarters is the tallest building in Europe and a unique example of a naturally lit and naturally ventilated skyscraper. The building was designed to be an ecological, low-energy building. In addition to the efforts done to lower the energy consumption related to the building operation (heating, cooling, lighting, etc), the design of the 60-story high rise in the center of the city allowed easy use for public transportation systems. There are more than 2500 employees and a large number of visitors in the building but there are only Commerzbank HQ in Frankfurt 300 car parking lots. The floor plan of the tower is an equilateral triangle with rounded corners and slightly convex sides. The floors of the building as well as the cores at the three corners are organized around a central atrium. Each floor has three wings, two of which serve as office space, the third forms part of one of the 4-storey-high gardens. The gardens (nine in total) can be used by employees as recreation areas and they provide the inner offices with plenty of daylight. The central core that is usual in high-rise buildings was replaced with a full-height atrium, divided into twelve-story sections and the support structure, circulation areas and ancillary rooms were accommodated in the three corners of the building. One of the nine gardens 12

15 Climate Control and Ventilation The building has a hybrid HVAC concept: a mixture of natural ventilation for indoor air quality control (IAQ) and thermal comfort control, mechanical ventilation for IAQ control and cold ceiling for summer comfort control. Mechanical cooling is provided by water-filled chilled ceiling systems instead of the traditional high-maintenance air conditioning systems. The rooms are heated by conventional convectors. For substantial energy savings and natural ventilation, the building is enclosed in a twolayer facade. Office windows towards the exterior have an outer glass sheet, a 16.6-centimeter thick ventilation cavity and a double glazed inner window. The outer glass sheet is fixed, but has top and bottom slots to ventilate the cavity. The inner windows are operable. It pivots inward from the bottom for ventilation. Gardens are used to provide fresh air to the atrium Normal operation (Natural Ventilation) Operation during extreme weather (Mechanical Ventilation and A/C) Internal atrium The double facade cavity creates a sheltered zone with controlled infiltration that enables the inner skin double glazed tilt windows to be opened at all levels despite external air pressures. The gardens are also ventilated and air is then fed to the atriums to naturally ventilate the internal atrium offices. These two systems allow natural ventilation through both sides of the floor plate at all levels. 13

16 WINTER OPERATION: Internal skin closed. Mechanical air conditioning warms building. Ventilation of the cavity continues, as this is not adjustable. SUMMER OPERATION: Internal windows opened to allow infiltrated external air in the cavity to ventilate the office spaces. The gardens provide atrium ventilation air to offices on the internal aspect. On roughly two-thirds of the days in a year, employees can regulate ventilation themselves by opening or closing the windows individually. Thermal buoyancy and general wind conditions are suitable for natural ventilation for most of the year, which creates the necessary low and high pressures that promote airflow. This limits considerably the amount of mechanical cooling or heating required. Automatically controlled windows in the gardens Lighting The building was also designed to make the best possible use of daylight. The transparency of the building and the glass partition walls between offices and corridors provide all work places with high daylight values. Transparent partitions allow for good distribution of natural daylight. As required by the German building codes, workers working under a normal height ceiling are to be no more than 7.5 meters from a window for natural light. The design limits the width of each leg containing the office areas to about 15 meters to allow for natural daylight. The offices towards the exterior receive natural 14

17 Backup fluorescent lights with integrated mechanical light from the environment. The triangular cooling (linear diffusers) atrium provides the inner offices natural daylight. The amount of incoming natural light is controlled through the manual louvers between the two layers of the exterior window. The louvers also prevent overheating from the glazing. The natural light is backed up with fluorescent tubes. The lighting fixtures, as well as the heating and cooling thermostat in the corridor and offices are automatically switched to a standby mode during unoccupied periods and switched on when motion is detected. In an office building, the electrical load for lighting is a considerable portion of the total electrical consumption. By partially adopting natural lighting, the energy consumption is reduced. The natural light adds vividness to the busy working life of the employees, and may potentially increase the health and effectiveness of the employee. Building Management System A critical part of the building that ensures proper interaction and optimal utilization of the natural ventilation and the mechanical ventilation systems is the Building Management System (BMS). The mechanical cooling and heating systems as well as the natural and mechanical ventilation systems are all automatically controlled by a BMS. The BMS ensures that ventilation, heating and cooling are all optimal and also allows employees a certain degree of control. Employees are able to control the temperature in their office individually but only within a given range. 15

18 Climate conditions, such as wind speed, wind direction, temperature, and humidity, are sent continuously to the BMS from data taken at 10 separate weather stations. There is at least one station per every eight floors. When outside conditions are suitable for natural ventilation, the windows at the gardens are automatically opened by the BMS to allow for natural ventilation of the atrium (summer operation) and the occupants are allowed to open the windows in the inner skin of their offices. Under extreme conditions (e.g. very low or very high outside temperatures, high wind pressure, etc) the BMS enables the mechanical ventilation system, closes the garden windows to prevent outside air from entering into the atrium (winter operation) and the windows of the inner skin of the offices are locked. The use of natural ventilation for a particular space will automatically shut off chilled ceiling air-conditioning. Under certain outdoor humidity conditions, the opening of a window could cause condensation to occur on the ceilings. Thus, based on information from the building weather stations, the BMS makes a decision whether or not to allow the operation of the natural ventilation system. Occupants are kept informed of operation conditions by a light located on control panels in each room. When the light is red, the mechanical ventilation is in operation and the windows are locked. When the light is green, the system is in the natural ventilation mode and the office workers are free to open the windows. Occupants can only open their windows using the control panel located at each office. Typically, when the outdoor temperature is above 25 C or below 3 C, mechanical ventilation is used. Users control lighting, shading, and window. 16

19 Stadttor Düsseldorf, Germany 17

20 The Building Düsseldorf s Stadttor (City Gate) was built on the southern end of the Rhine tunnel. Interestingly enough, the busiest highway in Düsseldorf runs underneath the building. It has a rhomboidal shape and is 75 meters high with 16 floors. Stadttor (City Gate) The trailblazing ecological design and operation of this building feature a double-skin facade with automatically controlled motorized windows for natural ventilation and a innovative system that uses sorption technology (used when conditions are not suitable for 56 m high internal atrium natural ventilation). The heating and cooling of the building is achieved using the facade, underground water and heating/cooling plates. The outer facade is a secondary skin suspended from the roof of the building like a glass curtain, which protects the offices against the traffic noise and pollution from the highway. Behind this facade there is a gap distance or 1.4 meters, which not only provides insulation but also is used as a walkway and gives the occupants the ability to walk inside the double-skin cavity for leisure and recreation. The interior facade consists of vertical pivoted windows of insulated glass. The building also features a 56- meter high atrium for natural ventilation, as well as natural day lighting. 18

21 Natural Ventilation Natural ventilation is controlled by a system of closing louvered vents located in front of each floor slab. Adequate natural ventilation of the facade cavity in summer means that little or no mechanical cooling in the offices is necessary. for interior conditioning. Double-skin facade with louvered vents in front of each floor slab The double-skin facade is used to create a greenhouse effect. When the outside air temperature is between 40 and 70 F, the building is ventilated through the windows to condition the interior air. This involves using open doors in the interior facade and motorized windows on the exterior facade, essentially providing fresh outdoor air at appropriate temperatures Extensive research was done in this building to determine the optimal shape, location and size of the outside air intakes and louvers to provide sufficient and adequate natural ventilation. The natural ventilation system is utilized only when the Detail of louvered vent in front of floor slab outside temperatures are between 5 and 20 C. Outside of those limits mechanical ventilation is used. Mechanical Ventilation In order to provide a comfortable interior climate when outdoor air temperatures are between 20 and 25 C, the system uses sorption technology, which is a combination of 19

22 exhaust air dehumidification and heating/cooling plates that continue to provide cool outside air during moderate summer weather. The sorption system uses a desiccant wheel to transfer latent energy (moisture) and sensible energy (temperature) between two non-mixing air streams (outside air used for ventilation and exhaust air). It basically operates as an energy recovery wheel. Typically during the summer, the sensible and latent energy of the hot and humid outside air stream is transferred by a desiccant wheel to the exhaust air stream. The end result is a very energy efficient method of producing dehumidified ventilation air. Heating and Cooling When temperatures rise above 25 C, cooling plates with copper tubes located in the ceiling of each space are used to condition the air for delivery to the space. The cooling plates are cooled using water from a large underground pipe system (this is possible due to the proximity to the Rhine). Water is a much better medium for cooling air than air and avoids many of the hygiene issues associated with air-to-air cooling. Using ground-cooled water to cool the building significantly reduces the energy consumption of the building, water pumps are the only major equipment required to be operated. The underground water does not circulate directly through the cooling plates, a heat exchanger, secondary loop and pumps are utilized for this purpose. During winter, the large facade cavity acts as a buffer zone, considerably reducing heat losses and radiation in the area in front of the windows. Heating of the building is accomplished using floor radiators. They use excessive steam from a power plant located in Düsseldorf. When outside temperatures drop below 5 C, the outside air is primarily conditioned through heat recovery without the use of primary energy. If needed, the heating/cooling plates can provide heat using the district heating loop connected to the building. The district heating loop also provides heat to the desiccant wheel if additional activation heat is needed during the summer for dehumidification. 20

23 The remarkable design of this building allows for its cooling, heating and ventilation loads to be satisfied throughout the year with absolutely no chlorofluorocarbons. There are no refrigeration cycles in this building. The sorption system in combination with the cooling/heating plates that use either ground-cooled water or district steam and the natural ventilation system are capable of satisfying the cooling, heating and ventilation loads of the building throughout the year. Building Management System A Building Management System (BMS) was installed in this building, which was of particular importance given the fact that a reduction in operating costs and a simultaneous need to increase personal comfort within the building were primary requirements in the design of the building. The BMS played a fundamental role in Automatically controlled window shutters in exterior facade coordinating and integrating all the different systems in the building from all the different manufacturers (i.e. natural ventilation, sorption system and heating and cooling) to insure their optimal performance and operation and to provide maximum comfort in the most energy efficient manner. Exterior facade The building is zoned by floor. Using the BMS, the climate for each floor is automatically controlled. When the temperature drops below 5 C, the louvers in the exterior facade are automatically closed and the mechanical ventilation system is enabled. Individual controls in each room allow the users to 21

24 go 3 C above or below the zone setpoint. Numerous individual room control units were required in this project with adjustable parameters to offer the necessary flexibility and functionality for the different room types. These individual control panels provide temperature control, changeover functions for the heating and cooling plates and the ability to offer user-defined parameters for individual rooms. In addition, diagnostic programs are used for constant monitoring of functions within the room control circuits. These programs immediately report problems to the operator workstation for follow-up by building management personnel. The BMS also operates a shading system used to control natural daylight in the spaces. The shading system is located inside the interior double-glazing skin. It consists of aluminum blinds that go down when the sun has been out for longer than 10 minutes and rise when the sun has been behind clouds for more than 10 minutes. Individuals can control the blinds using a control pad located in each room. These blinds provide adequate natural light levels in the spaces and since they are so close to the internal skin of the building, a significant temperature rise is caused in the cavity (gap in between the double-skin) that promotes the thermal buoyancy or stack effect necessary for natural ventilation. An additional benefit of these internal blinds is that they can be lowered even during high wind velocities in the cavity. The BMS uses input data from a weather station located on the roof, which measures wind direction, wind speed, light intensity and direction, and temperature. There are also eight temperature sensors on each facade, as well as four wind speed sensors located in the atrium. 22

25 Institut du Monde Arabe Paris, France 23

26 The Building The Institut du Monde Arabe South facade of the IMA (IMA) is located along the Seine roughly at the boundary of historical Paris and a more modern urban fabric to the southeast, the beginning of which is marked by the university building at Jussieu. The building consists of a museum, a library, an auditorium, offices and meeting rooms assembled within two wings separated by a courtyard opening out toward the Cathedral of Notre-Dame. The South Facade The south facade is made up of numerous and variously dimensioned metallic diaphragms set in pierced metal borders. There are 240 panels hermetically sandwiched between glass and each one incorporates the geometric forms (circles, squares, octagons, etc) used in Arab Islamic architecture. The changes to the irises can be clearly seen from the interior while externally a subtle density pattern can be observed. The whole effect is like a giant Islamic pierced screen. Interior side of the panels Exterior side of the panels These diaphragms are operated by electronically controlled servomotors that respond to changes in the intensity of the sun. They (the diaphragms) operate like a camera's shutter, opening and closing to control the intensity of light in the interior. 24

27 Diaphragm Control and Operation A central computer receives the solar intensity and the outside temperature data from an exterior sensor located on the roof, and based on a user-defined setpoint for temperature and solar intensity, all the servomotors are commanded by the computer to either open or close the diaphragms. Solar intensity is the prevailing condition used to control the diaphragms. If sunlight levels are too high (e.g. very sunny day during summer) as compared to the predefined setpoint, the diaphragms are commanded close by the central computer to regulate the intensity of light in the interior and to minimize solar heat gain. Digitally controlled However, when the outside temperature falls servomotor below 5 C, the computer overrides the solar intensity condition and commands all the diaphragms open to maximize solar heat gain. The servomotors operate based on a digital signal from the computer, which basically means that the diaphragms can only be either totally opened or totally closed. There is no modulation. To avoid short cycling of the servomotors, the computer has an adjustable time delay of 10 minutes before any new action is taken. This prevents the operation of the diaphragms under temporary conditions such as passing clouds on a sunny day, etc. Even though there is only one sensor to control Sequence of operation A1-I B1-I C1-I D1-I A2-I B2-I C2-I : : : A6-II B6-II C6-II D6-II A B C D I II 25

28 all the diaphragms, not all the panels are operated at once and as a whole. Instead, the facade was divided into 8 sections and each section was divided into sub-sections of 5 vertically arranged adjacent panels. The 5-panel sections are then sequentially operated to smooth the operation of the system and allow for gradual changes in the luminosity of the spaces. This has a much better visual impact on occupants and visitors. Maintenance The panels require constant maintenance and cleaning, especially the inside glass covers, which takes a good portion of the maintenance budget every year. Cleaning of the outside glass covers is only performed once a year. All the diaphragms and their metallic components can achieve considerably high temperatures. This causes continuous expansion and contraction of all the parts, joints and moving parts of the diaphragms. Of course, this is a major cause of failure in these panels, as moving parts within a Mechanical fuse panel very often get stuck because of the excessive friction on the expanded joints. Each actuator or servomotor is capable of putting enough force on the structural components of the panel to completely deform and permanently damage them. Thus, to prevent the diaphragms and all the internal components of a panel from being irreversibly damaged when the actuator is energized, a mechanical fuse or pin was implemented in the design of each panel to serve as a link between the actuator and the rods of the panel that operate the diaphragms. This pin is made of a material with a significant lower strength than the material the rest of the components in a panel are made of. When the actuator is energized and there is excessive friction in the moving parts and joints of a diaphragm that cause them to get stuck, the pin or mechanical fuse breaks and the actuator is free to move before any damage is caused to the panel and its components. Because of budgetary constraints, 10% of the panels are allowed to fail before any single one is repaired. 26

29 Personal Viewpoints & Analysis KfW This building has an outstanding system to maximize utilization of natural daylight and thus minimize the energy consumption of traditional artificial lights. The entire system is automatically controlled from a central panel located in each office and is flexible enough to accommodate individual preferences by the occupants. These features make this system extremely versatile and energy efficient. Furthermore, it has the added benefit of a naturally lit working environment, which has a positive psychological effect that can improve employee productivity. It is my opinion that in this case, the installation of such a sophisticated, complex and unique system was probably more driven by marketing reasons (to create a showcase and a good image to the public and customers) than by energy savings. The cost of implementing such a system would probably be financially prohibitive in almost any other application (i.e. without those additional driving forces). Commerzbank This skyscraper is a good example of an environmentally friendly design. Natural daylight and natural ventilation is utilized during most of the year and everything is controlled from a central computer that decides based on information provided by the weather stations if conditions are suitable or not for natural ventilation. The double skin facade in combination with the internal atrium ventilated through the gardens is a very innovative design that not only complies with the stringent local building codes but also achieves high levels of energy efficiency since very little mechanical cooling or heating is required throughout the year in the entire building. Proper and frequent preventive and corrective maintenance in this building becomes a critical factor in achieving a high energy efficiency level. Having automatically controlled windows throughout the building requires continuous maintenance to ensure their proper 27

30 operation. Deferred maintenance and/or a limited maintenance budget could then become a potential problem in this building over the long run. Stadttor When temperatures are between 5 and 25 C, natural ventilation is used to condition the building. Outside those parameters, sorption technology is used for ventilation. The building uses waste heat from a power plant for heating during winter or during summer for dehumidification in the energy wheels and underground water for cooling. This means that the building utilizes very little primary energy from the city for heating and cooling of the building throughout the year. This is a technologically advanced building that is extremely energy efficient, environmentally friendly and uses no chlorofluorocarbons in providing cooling and heating. This is truly an example of a building for the future and a remarkable accomplishment of teamwork between architects and engineers. IMA This building features a unique design that integrates technology with historic Islamic values. The diaphragms are controlled to maintain a certain level of luminosity on the interior and also to control the heat gain from solar radiation. The effect is a very impressive dynamic facade that seems to be alive and that reacts to changes in the environmental conditions. The cost associated with maintaining this system operating properly is significantly high though. 240 panels, each with numerous moving parts and diaphragms that expand and contract countless times every day because of the solar radiation will tend to have a high failure rate. Constant cleaning and repairs will be required, which can quickly add up to significant maintenance expenditures. This will be a maintenance challenge for decades to come. I originally thought there was one sensor located inside each room to control a small group of diaphragms to maintain a user-defined illumination level or setpoint. On the contrary, all the diaphragms in this building are controlled from a central computer based on data from a single sensor located on the roof. This makes the operation and installation of the system much simpler. 28

31 Final Statement Traveling to different countries and seeing with my own eyes what they have done in some of their buildings, has been a very rewarding experience for me. I was very much fascinated by some of the innovations that have been implemented in some of those buildings. The approach taken in the design of these buildings was not driven only by economics -as it is in most cases in the United States- there were other maybe even more important driving factors such as the need of creating a building that is environmentally friendly or a building that will stand out for its innovations, etc. This approach is what makes it possible for technological advances that would otherwise be overlooked by architects and engineers because of their prohibitive first cost to get implemented. My original intention of learning what other countries have done or are doing in regards to the integration of control systems with mechanical and architectural elements in a building was very much fulfilled by these travels, despite the fact that lack of time did not allow me to complete my original travel itinerary. I was also able to study and learn about some of the innovative solutions that have been implemented to improve the overall energy efficiency of buildings. Automatically controlled windows to provide natural ventilation and automatically controlled blinds or diaphragms to provide natural daylight and a constant level of illumination are some examples. Even though most of these innovations may never get implemented in the North American industry, it is certain from these initiatives taken by these European countries that not only the US but also the rest of the world will, at some level, benefit. This experience was overall an excellent opportunity to get some exposure on how other developed countries are coping with the energy efficiency issues and challenges that the world is facing today. I am most grateful for having been granted with this opportunity and would not hesitate for a minute to do it all over again if I had the chance. 29

32 The End 30