A potential client is considering installing a biomass boiler in a property at a remote highland location. The existing kerosene boiler is rated at 17 kW and quoted as having an efficiency of 86%. The client is presently paying 2242/yr for fuel, at a price of 0.06 p/kWh. You have undertaken a survey of the property and have determined that through additional insulation and draft proofing, the building Design Specific Heat Loss is currently 380 W/K. The biomass boiler supplier can provide units rated at 10 kW, 12 kW, and 15 kW. i) Determine the annual heat purchased, and the annual heat delivered to the property before any insulation upgrading and improvement. (2) ii) For a design internal temperature of 200, and an external minimum temperature of -10C, specify which of the three boiler options you would recommend. Also, given the same temperature rating, estimate the DSHL for the house prior to renovation. (4) iii) Building glazing, occupancy patterns and appliance use provide a useful annual gain of 9100 kWh. To a base internal temperature of 18C, the annual Degree Days figure for the location is 4192 DD. Determine the building annual heat input required for the biomass boiler. (3) iv) Considering the RHI Tier payment scheme (Tier 1 = 0.076/kWh), determine the annual RHI income for the biomass system. (2) v) The manufacturers quote an efficiency of 93% for the wood pellet boiler. Determine the annual running cost (accounting for Rhl payments), and hence the fuel cost saving if the pellet purchase price is 0.04/kWh. (3) vi) What is the difference between a "Passivhaus" and a "zero carbon" home? What are the advantages and disadvantages of such buildings? Also, briefly ways of correcting these issues. (6)