Economic analysis of small-scale cogeneration. You are considering an investment in three 60- kW microturbines, that generate both electricity and DHW, for a large apartment complex. The microturbines will displace output from the existing natural gas-fired boiler for DHW such that 100% of the demand is met by the microturbines. The microturbines start running at 5 a.m. in order to generate DHW for the morning peak; they then run continuously at full power until they have made enough DHW for the total day’s demand. Thus, the cogeneration system supplies 100% of the DHW need. It can be assumed that when the system turns off for the night, there is enough DHW in storage to last until it comes back on the next morning. The prices of gas and of electricity are $10.75/GJ and $0.105/kWh, respectively. The turbines cost $85,000 each, with an additional $0.02/kWh produced maintenance contract cost; the project life is 20 years with an interest rate of 3%. The turbines convert 26% of the incoming energy to electricity, and 55% of the incoming energy to DHW. The existing boiler system transfers 83% of the incoming energy to DHW. (a) To the nearest whole hour, what time does the system turn off? (b) Determine the net present value and state whether or not the investment is economically viable. (c) If the complex uses 8000 kWh of electricity per day, what percentage of this total demand do the turbines deliver? (d) Suppose that for 5 months of the year (assume 30 days/month), the system can provide heat for space heating with no additional upfront capital cost and is therefore able to run 24 hr/day. How does the answer in part (b) change?

Respuesta :

For part (a), the gadget typically turns off for the duration of the night when sun panels are not producing power.

For element (b), to determine the net gift cost of the investment, you'll need to calculate the present fee of all coins inflows and outflows associated with the challenge. If the internet present price is tremendous, then the funding is economically possible.

For part (c), if the mills deliver a certain amount of strength, you could calculate the proportion by using dividing that quantity by means of the full demand of 8000 kWh according to day.

For element (d), if the system can provide heat for area heating for 24 hours an afternoon for five months with no extra value, it might boom the coins inflows and doubtlessly improve the internet gift price of the investment. You might need to recalculate the internet gift cost taking into consideration this additional gain.
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