Consider a house in winter. It is heated by the sun at a rate of 2 kW. Electrical appliances in the house are drawing a total of 4 kW. Although all the windows and doors can be considered tightly closed, heat is lost through the exterior (e.g., through the insulation) at a rate of 12 kW. Compressed natural gas (CNG) is delivered to the house through a pipe, and an associated furnace heats the house at a rate of 6 kW. Sketch a stick diagram of the house along with wires supplying electricity to the house and a pipe supplying CNG. Sketch a system boundary around the house. Draw arrows representing each energy flow with the convention that an arrow pointing out of the house represents an energy loss from the house. Label each arrow with a descriptive name and its quantitative value with units. Identify any energy flows that are accompanied by flows of mass.