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KNX city Part 4: Energy management. Definition of Energy efficiency. …in terms of the building „The objective of energy efficiency in the building is to save all forms of energy which are brought to the building from the outside by energy carriers such as gas, oil, electricity and water.“
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Definition of Energy efficiency • …in terms of the building „The objective of energy efficiency in the building is to save all forms of energy which are brought to the building from the outside by energy carriers such as gas, oil, electricity and water.“ • … in terms of cities „ The objective of energy efficiency in cities is to save primary-energy such as fossil energy sources“ • …in terms of „power supplies“ „The objective of energy efficiency in power supplies is to reduce the electrical energy harvest from fossil energy sources and to increase the energy harvest from renewable energies“
Field of applications in the buildingExamples: • Commercial buildings: • Avoiding of heat losses occuring by opening windows over weekends • Avoiding heat losses by KNX heat and air conditioning control • Saving electrical energy by light control via presence-detection • Saving electrical energy by light-intensity and day-light control • … • Domestic homes • Saving energy by visualization of actual and total energy consumptions. • Saving energy by heat- and and air-conditioning controls • Saving energy by louver-controls (avoiding over overheating) • Comfort Aspects • New applications: Demand Response, Demand Side Management • …
KNX solutionsClassic fields of application • KNX offers total building controls • Lighting • Blinds & shutters • Security systems • Energy management • HVAC Systems • Monitoring systems • Remote control • Metering • Audio/Video • White goods How to realize an energy management?
KNX control Systems • Controller • A controlller adapts an „actual value“ to a given „setpoint value“ and keeps the „setpoint value“ without a deviation between both values • Example: A heating controller shall operate the heating in a way, that the room temperature contains 23°C • Control and metering task • The „actual value“ must be measured with a „sensor“ • The controller proceeds the deviation and controls an „actuator“ • The „actuator“ starts an action • Example: A KNX thermostat (controller) measures the room temperature with a KNX temperature sensor and controls a valve of the heating system with a KNX electronic actuator
KNX Open-loop-control systems • Open loop Controller • A controller changes the „actual value“ in dependence of an input value without getting a feedback about the real changes of the actual value • Example: A switching actuator is controlled in dependence of a presence-detector • Control and metering task • Sometimes the setpoint value is set proportional to a measured value • Example: The angle of a louver is controlled in dependence of the sun light. The sun light is measured by a weather-station. The setpoint value is set by a fixed table which describes the relation between angle and sun light. • Smart metering is a precondition • Only the interaction between metering and actuators can realize an energy management
Smart MeteringSmart Metering as a precondition for energy management
KNX solutionsExample: Open-loop light control • Presence-detectors detect if persons are present in the room • Yes: lights will be switched on • No: lights will be switched of • Application is often used for restrooms in commercial buildings Electrical Energy can be saved
KNX solutionsExample: Open-loop blinds & shutters control • Shutter-angle can be controlled in dependence of the position of the sun • Application is often used in Domestic Homes Energy of systems for air conditioning can be saved
Cascaded heat control:Example: HVAC control • Cascaded control of a floor heater and an air conditioning system • The thermostat measures the actual temperature and adapts the room temperature to the setpoint temperature Thermal energy can be saved
Cascaded heat control:Example Control-System: HVAC Control • Advantages: • One thermostat controls two heat devices • More than one control panel can be used for setting the setpoint temperature of the thermostat • The cascaded control balances the slow thermal behavior of the floor heater with a fast thermal behavior of the air conditioning system • Both thermal systems don‘t control against each other • The control of several thermal systems such as floor heaters, heatpumps, etc. is with KNX possible
Demand Side Management • Definition of Demand Side Management • „Demand Side Management describes the process to change the energy demand of customers by incentives in order to get a better coverage of the energy generation“ • KNX can help by adapting loads
Demand Side Management:Control The implementation with KNX is possible
KNX Energy Management solutions • More solutions can be found in:
Contact Lutz Steiner lutz.steiner@knx.org KNX Association Brussels