There are a few ways to do this:

modelObjects = model.getHVACComponents

waterHeaters = []
modelObjects.each do |obj|
  if obj.to_WaterHeaterMixed.is_initialized
    obj = obj.to_WaterHeaterMixed.get #converts #this line converts the object to a waterHeaterMixed object
    waterHeaters << obj
  end
end

waterHeaters.each do |obj|
  puts "#{obj.name}"
  puts "#{obj.class}"
end

#Alternatively 
waterHeaters = model.getWaterHeaterMixeds

There are a few ways to do this:

modelObjects = model.getHVACComponents

waterHeaters = []
modelObjects.each do |obj|
  if obj.to_WaterHeaterMixed.is_initialized
    obj = obj.to_WaterHeaterMixed.get #this line converts the object to a waterHeaterMixed object
obj.to_WaterHeaterMixed.get
    waterHeaters << obj
  end
end

waterHeaters.each do |obj|
  puts "#{obj.name}"
  puts "#{obj.class}"
end

#Alternatively 
waterHeaters = model.getWaterHeaterMixeds

There are a few ways to do this:

modelObjects ModelObjects = model.getHVACComponents

waterHeaters = []
modelObjects.each ModelObjects.each do |obj|
  if obj.to_WaterHeaterMixed.is_initialized
    obj = obj.to_WaterHeaterMixed.get
    waterHeaters << obj
  end
end

waterHeaters.each do |obj|
  puts "#{obj.name}"
  puts "#{obj.class}"
end

#Alternatively 
waterHeaters = model.getWaterHeaterMixeds