Weak current College】 【small-scale biogas system cost analysis.

<br> <br> A introduction <br> <br> Since the 1980s, along with the development and utilization of solar energy, photovoltaic industry become the world's more than the fastest high-tech industry - with the countries of the world importance of .renewable energy and solar cell conversion efficiency, photovoltaic industry is growing at rapid speed, rapid development, especially for those living scattered, inconvenient, it is difficult to extend the public power grid adoption to solve the problems of the region with electricity, solar power generation .system is a huge potential market. <br> <br> However, in some small user of photovoltaic power generation system design, often there are some problems: eg in order to meet the requirements of the low cost, juice capacity obviously inadequate; blind .pursuit of high reliability requirements cannot blackout, greatly increased the investment costs. Battery capacity is too large, not only increased investment, resulting in a waste, but also easy to form a charge. This article in accordance with the small PV power generation system design ., on the impact of its power generation system cost analyses the main factors, to meet the workload coverage of the guarantee system optimization, and economics. <br> <br> Second PV system cost analysis <br> <br> Photovoltaic power generation system .life cycle cost C is: <br> <br> C = CsW? + Cbb (1) <br> <br> Type: Cs-photovoltaic components of the price ($ / kWh); W for solar cell peak wattage; Cb .unit for batteries; b for the battery capacity. <br> <br> System constraint functions are: <br> <br> LOLH (w, b) = TK (2) <br> <br> Type: TK as the user .has agreed to terms with losing power hour mi: LOLH (w and b) for the hours lost power to TK, the peak wattage Wc solar cells and batteries with a total capacity not b. <br> <br> Top-visible, the .cost of PV system with photovoltaic modules and battery capacity has a linear relationship, and the number of hours lost power. <br> <br> Three cost factors <br> <br> 1 battery capacity <br> <br> In the design .of battery capacity, through comprehensive consideration of solar PV system installation site of the largest contiguous rainy days and load maximum outage hours to determine the number of days of the subsistence of battery. In addition battery capacity and battery discharge rate and temperature. <br> .<br> (1) battery discharge rate effect on the capacity of <br> <br> Battery capacity with discharge rate of reduction increases accordingly. <br> <br> <br> <br> Type: s is the average discharge rate ., battery (h): number of days for subsistence, D Pi to load power (w); Ti-load work time (h); DOD to battery for maximum depth of discharge. <br> <br> The battery discharge rate and .working temperature can be identified capacity correction coefficient 1. <br> <br> (2) of the environmental effects of temperature on the battery <br> <br> Battery capacity: <br> <br> Type: Ld is a daily and .load capacity (kwh); D the number of days for subsistence, L is the decay rate; n is the number of battery; Vb as nominal battery voltage (V), the occasion for lead-acid batteries, 1 for 2Vt battery voltage discharge .rate of volume correction factors. <br> <br> Because when the battery temperature drops, the battery capacity is reduced. Their trends as shown in Figure 3. <br> <br> Effect of temperature, battery for maximum discharge depth: < .br> <br> DODb = DODx [1 10 a (t-25)] (5) <br> <br> Type: a-battery temperature coefficient (1 / ° c). <br> <br> Battery capacity could .be amended to read: <br> <br> <br> <br> 2 the capacity of PV modules <br> <br> Solar cell component capacity calculation formula: <br> <br> <br> <br> Type: .EL for one year the consumption of electricity in load (the power) (kwh / year); Pas to standard conditions (AM1.5, Sunshine intensity to 1000W/m2, solar cell temperature of 25 ° c) solar array output (Ah) .; 2 as the output efficiency of PV modules; t is a solar cell component's peak hours. <br> <br> Solar cell component of peak hours of estimation method for T = I <br> <br> Calculation and analysis of four instances .<br> <br> Mongolia sonid right banner (42 degrees north latitude, longitude 28 112 degrees 57 minutes) of a PV household system as an example, daily consumption of about 2.0 degrees year allowable outage hours 8 hours, ie load coverage of 98 .%. The area of solar energy resource efficiency according to meteorological data shown in table 1. <br> <br> Based on the table, you can calculate the horizontal sonid right banner's average annual radiation total 1.59MWh/m2/yr. The installation .angle taken twice a year, that is, the method - September 4 to 30 degrees, the remaining months to 60 degrees. Can be tilted installation of PV components of the total average annual radiation as 2.0MWh/m2/yr. By ±: the .area in December average daily exposure of the smallest, the PV system design time, this month-based computer for PV modules and battery capacity simulation based sauce. <br> <br> This example selects the deep discharge of lead-acid battery, which .is 25 ° c and 80% depth of discharge. According to the place of sunshine hours and the average minimum temperature for the month, days of the subsistence desirable battery is 6 days, by type (3) can be concluded that the discharge hour 59.5 .hour figure 2 can be found hours amended battery with a capacity of 70 per cent, by type (5) available to 61% depth of discharge. The rated capacity of battery 200A.h, Coulomb efficiency to 86%. Figure 4 shows, the .initial cost of power generation system and the total cost as the battery capacity increases, batteries, each additional 6@200A.h, its total costs increased 3 percent. Battery's discharge depth with capacity increases and decreases. When the battery has a capacity of 72 .@ 200A.h, without sunshine 6 days after its discharge depth of about 60 per cent less than the battery allows discharge depth 61 percent, the battery will not discharge. By type (6) of the battery capacity is 72@200A.h, .and Figure 4. <br> <br> You can see from Figure 5, as the photovoltaic components power increases, the total cost of the system and generating capacity will rise. PV modules power each additional 0.lkW, total cost of about 3.7 .per cent increase, the increase in generating capacity of about 72 per cent. <br> <br> Figure 6 shows the user load unchanged conditions, along with the monthly average daily exposure of increase in the capacity of PV modules, generating total cost decrease .accordingly. This month's average daily exposure to meet or exceed 3.8kW/m2/d, the required capacity of PV components meet minimum 0.9kW, generating cost is minimum. <br> <br> System outage hours different TK determines the load different coverage .. Figure 7 is the system in different load coverage, that is, different outage hours TK, PV modules and battery change relations between. As the load increases the coverage (outage hours reduced), PV modules and increases the capacity of the battery. By .Figure 7, in average radiation dose the lowest for the month of December, to ensure the system 98 per cent of the load coverage (outage hours 8h/year), the battery is 72@200A.h, photovoltaic components of capacity 2.0kW. .This value and pass-(7) juice count of PV components capacity 1.9kW similar. <br> <br> Five summary <br> <br> A good small PV power generation system not only to low cost and high load, ie loss .of coverage by hour. Small PV power generation system, PV modules, each additional O.1kw, power generation system costs approximately 37 per cent increase, the increase in battery capacity each, total cost of about 1200A.h increased 3 percent. So according .to PV system installation site of the solar energy resources (such as a solar month average daily exposure, the largest non-sunshine time, a minimum temperature of the year, as well as the user the maximum allowed number of lost hours) reasonable choice of .PV modules and battery capacity to achieve the lowest cost of power generation systems, and guarantee optimal system operation. <br> <br> <br>.