|Type of building
|Number of KNX devices
||EFdeN is a solar, energy efficient, sustainable, intelligent house, designed and built exclusively by students for the future communities. It has a greenhouse intended to the “urban farming” concept and which is integrated in the prototype’s HVAC strategy. The functioning of the house is based on both active (i.e: heat pump, PV system, reinforcement BMS) and passive strategies (i.e: PCMs, natural ventilation), the house producing more energy than it consumes. But EFdeN is much more than a prototype as it grows as a team, creating professionals and sustaining the development of the community, over 200 students being involved in it. Also, EFdeN is Romania’s representative in the finals of Solar Decathlon Europe 2014 and it now becomes The First Research Center for Comfort Conditions from Romania. Its new purpose is to analyze and test all aspects of a dwelling’s comfort, carrying on with the successful collaboration between students, professors, companies and public partners.
|Main technical highlights
||The system had to be easy to implement, since most of the students involved in the electrical department were from Faculty of Building Services, with no strong practical and/or programming basis. With the ETS software the devices were easily linked together without programming skills needed. Due to its flexibility, the system has easy commissioning and maintenance; the whole house functionality won’t be affected if a device failures. And last but not least, the monitoring system of parameters like CO2, temperature, humidity, energy, gives the user real-time overview of the environment.
|Benefits of KNX
||To meet the demands of a modular building, easy to assemble and disassemble, satisfying the SDE competition and research center demands, the need for a modular, decentralized and intelligent automation system was born. Due to its features, the KNX network was the perfect solution that allowed us to integrate all equipments and systems from various manufacturers, having the flexibility to adapt the BMS to the situations that we faced. We integrated subsystems such as lighting control, HVAC, energy management with remote user interface, in a single decentralized system, stable and extendable.
|Which functions were realised with KNX
||Monitoring and control functions were realized for all house services and system: air-water heat pump (HP), vacuum tube collectors (VTC), radiant panels, photovoltaic system (PV), heat recovery unit (HRU), lighting, ventilation, cleaning system for PV, greenhouse irrigation, etc. We used more than 35 KNX devices like homeLYnk; CO2, temperature, humidity, brightness, smoke and presence sensors; push buttons, binary inputs; analogue, dimmable and switching actuators; weather station; all from Schneider. The heat pump is linked to the KNX network via ISG Web KNX IP gateway from Stiebel-Eltron.
||The light intensity in the environment is monitored by light intensity sensors and will give feedback to dimming ballasts, in order to maintain a constant light level throughout the day. Also the light level can be controlled from the push-buttons. For switching light control we used switching actuators, presence sensors and push-buttons, this type of control being used for the greenhouse, exterior, technical rooms, lobbies and bathrooms lighting.
||External solar shading is one of the most efficient ways to control the comfort conditions of a house, so we installed a controllable system to adjust shutters depending on the position of the sun, optimizing the avoidance of overheating. In winter, they may be adjusted so the greenhouse benefits from the sun heat, and they can be closed at night reducing heat loss. Controlling these with the shading system we would save up to 600kWh/year. Daylight levels can be enhanced, levels of glare reduced, using the brightness level sensor. Due to the wind sensor the shading systems automatically close.
|Heating, ventilation, air conditioning
||High air quality is maintained by the house ventilation control system, which is linked to temperature, CO2 and humidity KNX sensors. The fresh air (taken from outside or greenhouse) is heated/cooled thanks to the HRU equipped with a heating battery (the thermal agent comes from a buffer tank linked to VTC, HP).
The air is introduced in each room via air dampers, controlled individually by KNX actuators. The temperature comfort is assured by radiant panels controlled by zone. KNX heating actuators controls by set point each valve’s zone. The thermal agent comes from the same buffer tanks.
||Another important feature is the automatic shutdown of the electric hob and oven. In case a fire breaks out, a differential temperature detector will trigger the emergency and immediately the central control unit shuts down electrical power to the stove and oven.
||In case a fire breaks out, smoke sensors give an alarm. For a higher wind speed, the shading system automatically closes. If a is window open, the ventilation system is shut down. In case a window is forced, a notification is sent to the user. All these alarms can be visualized either remotely, or local.
||Although an indirect approach, the whole project was designed to optimize energy consumption.
A direct approach would be to pre-heat the room environment to welcome the people in a comfort-controlled environment. The pre-heat process can be a slower one in order to reduce energy consumption.
||Multiple energy meters are used to be able to break down energy consumption. We have meters for consumed energy, produced energy, stored energy, lighting, sockets, electrical vehicle charging, BMS, laptop/TV, plumbing, HVAC.
All these meters are connected to the KNX system and can be used to interact with a smart grid.
|Audio / Video
||We intend to integrate the TV and audio systems to control them remotely via the KNX network from the user interface due to IR to KNX gateway from Zenio.
||The human machine interface is compatible with a large number of mobile devices and operating systems, such as tablets, smartphones, etc. The web based visualization can be accessed via internet from all over the world.
We have floor plans and system diagrams (photovoltaic, metering, heating, cooling, ventilation, sensors) both as overview and detailed screens. Trends can show overview regarding thing like energy consumption or comfort parameters evolution.
|Interfaces with other systems
||The heat pump controller is linked to the KNX system via the ISG Web KNX IP which is gateway between CANOpen and KNX. The Grundfos circulation pumps communicate via Modbus RTU to homeLYnk. The information from all the RTD sensor from the HVAC system is collected with a TWIDO plc and transmitted homeLYnk through same Modbus network. And last but not least, for the research purposes we mounted several thermocouples in the ventilated facade and in between wall layers. All collected data from these sensors, stored in a data logger, are transmitted via Modbus TCP communication to homeLYnk.
||Through the homeLYnk webserver we can access and control elements of the KNX system.
We can monitor sensor values (temperature, CO2, humidity, brightness, wind) or equipment status (magnetic contacts, smoke detectors) or energy meter values.
We can control lighting, shading systems, HVAC equipment, water pumps.
All these through the web interface.