Class: Pvwatts

Inherits:
Object
  • Object
show all
Defined in:
lib/pvwatts.rb

Overview

Wrapper around the www.nrel.gov/rredc/pvwatts/ web service API. Calculates the Performance of a Grid-Connected PV System. Use of the Pvwatts web service is restricted to authorized users. For information on obtaining authorization, contact [email protected]

See Also:

Constant Summary collapse

DEFAULT_DERATE = 
0.82

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(api_key) ⇒ Pvwatts

Create an instance of the API wrapper.



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# File 'lib/pvwatts.rb', line 24

def initialize(api_key)
  @api_key = api_key
end

Instance Attribute Details

#api_key ⇒ Object (readonly)

Returns the value of attribute api_key.



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# File 'lib/pvwatts.rb', line 18

def api_key
  @api_key
end

Instance Method Details

#yearly_production(opts = {}) ⇒ Hash

Calculate the estimated yearly production based on passed options.

Options Hash (opts):

  • :latitude (String, Float) —

    Latitude coordinate of the location.

  • :longitude (String, Float) —

    Longitude coordinate of the location.

  • :dc_rating (String, Float)
  • :tilt (String, Integer)
  • :orientation (String, Integer) —

    Orientation or azimuth value.

  • :shading (String, Integer) —

    A percentage value between 0 and 100.



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# File 'lib/pvwatts.rb', line 40

def yearly_production(opts={})
  Rails.logger.debug("pvwatts yearly prod called") if Object.const_defined?(:Rails)
  keys = opts.keys 
  client = Savon::Client.new("http://pvwatts.nrel.gov/PVWATTS.asmx?WSDL")
  @latitude, @longitude = [opts[:latitude], opts[:longitude]]
  @dc_rating, @tilt, @orientation = opts[:dc_rating], opts[:tilt], opts[:orientation]
  @shading = opts[:shading]
  if @latitude.nil? || @longitude.nil? || @dc_rating.nil? || @tilt.nil? || @orientation.nil? || @shading.nil?
    raise ArgumentError, "passed -> latitude: #{@latitude}, longitude: #{@longitude}, dc_rating: #{@dc_rating}\
    tilt: #{@tilt} orientation: #{@orientation} shading: #{@shading}"
  end
  req = prep_request(@latitude, @longitude, @dc_rating, @tilt, @orientation, @shading)
  
  response = client.get_pvwatts{|soap| soap.input = "GetPVWATTS"; soap.body = req }
  rdata = response.to_hash
  if rdata[:get_pvwatts_response] && rdata[:get_pvwatts_response][:get_pvwatts_result] && rdata[:get_pvwatts_response][:get_pvwatts_result][:pvwatt_sinfo]
    @production_data = {}
    @pvwatt_info = rdata[:get_pvwatts_response][:get_pvwatts_result][:pvwatt_sinfo].compact
    @pvwatt_info.each do |el| 
      if el.respond_to?(:has_key?) && el.has_key?(:month)
        @production_data[el[:month].downcase] = el[:a_cenergy].to_i
      end
    end
  else
    raise 'Problem with the pvwatts response'
  end
  @production_data
end