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File Descriptions, Equations, Tips

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Wilson Chiang edited this page Sep 26, 2015 · 3 revisions

Metadata file (updated Sept.16/15):

Updated metadata file is attached (Hackathon Data Description and MetaData (revised 16 Sept 2015).xlsx). It explains all parameters included in the Hackathon dataset and contains household data. Raw sensor data is not included in the metadata folder but will be available in the cloud, on USB sticks, and via a dropbox link.

Sensor Layout diagram (updated Sep.24/15):

Updated Sensor Layout Diagram is attached (Sensor Layout.pdf). It shows the placement of the 22 sensors within the Solar Boiler System.

Solar Boiler System - overview:

Attached is a diagram of how the Solar Boiler System works (Solar Boiler System Diagram.pdf). Below is a verbal description.

Light from the sun strikes the solar collector(s) and heats the black metal absorber underneath the glass cover. This heat is transferred to a non-toxic anti-freeze solution (propylene glycol and water) that is pumped through the collector and returns to the Solar Boiler (the heat exchanger with solar powered pump). The hot glycol then transfers heat to the water in the storage tank via the Solar Boiler's heat exchanger. The water is heated repeatedly in this fashion until the solar tank is hot. The Solar Boiler System is used as a domestic water pre-heater in conjunction with your conventional domestic water heating system. Cold water enters the Solar Boiler for initial heating, and is then delivered to the backup or conventional heating system for final heating as required. The conventional system is typically fueled by oil, electricity, propane, natural gas, etc. Conventional energy requirements can be reduced substantially by using the Solar Boiler, and on many days the Solar Boiler will provide ample hot water without the backup (conventional) heater turning on. In most families, the Solar Boiler will displace up to 65% of the water heating requirements. A typical system for a family of four would include two solar collectors (6 square meters), 270 litres of solar water storage and a photovoltaic module to drive the glycol pump.

Solar Water Heating – general/technical reference (RETscreen textbook):

Contains general and specific information relating to solar water heating systems. A good general and technical. Attached: RETScreen_Textbook_SWH.pdf Example Monitoring Systems: Example Solar System Monitoring pages for two different installations, one with oil and one with electricity auxiliary heater (includes system diagram, useful statistics and graphs): http://www.welserver.com/WEL0812/ http://www.welserver.com/WEL0813/

Example Visuals/Apps:

Below (and attached) are examples of useful visuals from the dataset. For any particular parameters it would be nice to zoom in (eg. view one parameter for one home over one hour), or zoom out (eg. view 2 or more parameters for any number of homes over one year or more).

  •      Solar energy delivered in kilowatt hours, kWh (eg. to solar collectors, to heat exchanger, to solar tank, to auxiliary heater, etc.)

  •      Domestic hot water (DHW) consumption in liters (daily, monthly, yearly, etc)

  •      Graphs of water and glycol temperatures

  •      Solar power/irradiance visuals

  •      Savings in dollars (eg. daily, monthly, yearly, etc)

  •      PV Module Status

  •      Pump Status (eg. which LED is ON: Pump On, Low Delta T, Collector Temp Hi, Storage Temp Hi)

  •      Solar Tank Indicator (eg. visual of a storage tank that changes colour depending on the temperature of the tank)

  •      Solar Map showing installations with colour coding to indicate solar energy

Example Calculations:

The equations below give instantaneous power (kW) and can be used to get energy (kWh) by integrating over time (accumulate/add values for each minute/timestamp over the desired time period).

  • 1- Energy (kWh) = Power (kW) x time (hours)
  • 2- Power from sun (kW) = HEAT_SUN = (SOLAR_POWER)*(COLLECTOR_AREA)
  • Note: COLLECTOR_AREA is the surface area in meters of the solar collector. It is 3 for SB32s (1-solar panel) and 6 for SB64s (2-solar panels).
  • 3- Power to solar tank from heat exchanger (kW) = HEAT_HX = (FLOW_GLY)((T_HX_GLY_IN)-(T_HX_GLY_OUT))(64.2/60000)
  • 4- Power to auxiliary heater from solar tank (kW) = HEAT_WATER_SOL = (FLOW_WATER)((T_WATER_SOLAR)-(T_WATER_COLD))(69.8/60000)
  • 5- Total power to heat domestic hot water (kW) = HEAT_WATER_TOT = (FLOW_WATER)((T_WATER_HOT)-(T_WATER_COLD))(69.8/60000)
  • 6- Cost of energy ($) = Energy (kWh) x Fuel cost ($/kWh)
  • 7- CO2 reductions/emissions (kg) = Energy (kWh) x CO2 emissions (kg/kWh)

Constants:

Useful constants for calculations:

  • Fuel cost (oil) = .20 per liter of oil
  • Fuel cost (oil) = .20 per kWh of oil
  • Fuel cost (electricity) = .17 per kWh of electricity
  • CO2 emissions (oil) = 2.6 kg per liter of oil
  • CO2 emissions (oil) = 0.42 kg per kWh of oil
  • CO2 emissions (electricity) = 1.2 kg per kWh of electricity
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