CN104318013A - Method for computing optimal inclination angles of distributed photovoltaic systems of roofs - Google Patents

Abstract

The invention discloses a method for computing the optimal inclination angles of distributed photovoltaic systems of roofs. The optimal inclination angles include the optimal inclination angles of single rows of photovoltaic assemblies and the optimal inclination angles of a plurality of rows of photovoltaic assemblies. The method has the advantages that the optimal inclination angles of the distributed photovoltaic systems of the roofs can be designed by the aid of the method under the condition that various factors are considered; the optimal inclination angles of the single rows of photovoltaic assemblies and the optimal inclination angles of the multiple rows of photovoltaic assemblies are computed under the condition that the minimum unit kilowatt-hour output electric costs of the photovoltaic systems are guaranteed, and the photovoltaic systems can be mounted at the optimal inclination angles according to actual conditions, so that the power generation efficiency of the photovoltaic systems can be improved.

Description

The optimum angle of incidence computing method of a kind of roof distributed photovoltaic system

Technical field

The present invention relates to the optimum angle of incidence computing method of a kind of roof distributed photovoltaic system, belong to photovoltaic system applied technical field.

Background technology

Constantly destroyed along with the nowadays development of traditional energy industry in recent years arrives bottleneck and the ecosystem, the mankind are more and more urgent for the demand of clean regenerative resource, and therefore, solar photovoltaic industry obtains significant development.Can become the main force of future source of energy industry for photovoltaic industry, its generating efficiency be deciding factor.

For the generating efficiency of photovoltaic system, its mounted angle can be described as very important influence factor.Therefore the method for designing of the optimum angle of incidence of photovoltaic system is concerned to the development trend in photovoltaic industry future.

Summary of the invention

For solving the deficiencies in the prior art, the object of the present invention is to provide a kind of effectively rapidly to the method that the optimum angle of incidence of roof distributed photovoltaic system calculates.

In order to realize above-mentioned target, the present invention adopts following technical scheme:

The optimum angle of incidence computing method of a kind of roof distributed photovoltaic system, comprise the optimum angle of incidence of single photovoltaic module and the optimum angle of incidence of plural number row photovoltaic module, it is characterized in that: the optimum angle of incidence of described plural number row photovoltaic module, its computing formula distributes as follows according to the ratio that blocks of front-seat photovoltaic module to rear row's photovoltaic module:

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos (1-x)}\×Q_{\max }}\×(1.0825-0.825x\×s)\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×[0.717-0.775\×(x-\frac{1}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×[0.4125-0.825\×(x-\frac{2}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Block ratio now do not generate electricity, do not do to consider;

Wherein, parameter meaning is as follows: the rent on roof is m, and roof is long is a, and wide is b; Single photovoltaic panel area is long is k, and wide is t; Single photovoltaic module cost is n, single photovoltaic module be in optimum angle of incidence and shadow-free blocks time annual generated energy be Q _max; The inclination angle of photovoltaic arrays is α, and the block ratio of front-seat photovoltaic module to rear row's photovoltaic module is x; Photovoltaic module battery row is s; The cost of every kilowatt hour generated energy is y; η _αfor the generated energy Q under unobstructed different angle and the generated energy Q under unobstructed optimum angle of incidence _maxbetween ratio;

The by-pass diode of each described photovoltaic module is provided with 3; The described roof side of being flat-top; In described assembly, every block battery is all be in perfect condition.

The optimum angle of incidence computing method of aforesaid a kind of roof distributed photovoltaic system, is characterized in that: the optimum angle of incidence of described single photovoltaic module, adopt " solar radiation calculation procedure " to calculate optimum angle of incidence.

The beneficial effect that the present invention reaches: the present invention is when considering many factors, the optimum angle of incidence method for designing of a kind of roof distributed photovoltaic system of proposition; Output energy cost is minimum when ensureing photovoltaic system per kilowatt, the optimum angle of incidence of single plural number row photovoltaic module being calculated, the inclination angle of the best can be installed according to actual conditions, improve the generating efficiency of photovoltaic system.

Accompanying drawing explanation

Fig. 1 is that single battery shade blocks number percent and affects statistical form to power;

Fig. 2 is η _αwith the function relation figure at inclination angle;

The cross section structure schematic diagram on roof, library, Tu3Shi Hohai University, Changzhou.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.

For the generating efficiency of photovoltaic system, its mounted angle can be described as very important influence factor.Therefore the method for designing of the optimum angle of incidence of photovoltaic system is concerned to the development trend in photovoltaic industry future.

Now design the optimum angle of incidence computing method of a kind of roof distributed photovoltaic system, comprise the optimum angle of incidence of single photovoltaic module and the optimum angle of incidence of plural number row photovoltaic module.

The optimum angle of incidence of plural number row photovoltaic module, its computing formula distributes as follows according to the ratio that blocks of front-seat photovoltaic module to rear row's photovoltaic module:

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos (1-x)}\×Q_{\max }}\×(1.0825-0.825x\×s)\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×[0.717-0.775\×(x-\frac{1}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×[0.4125-0.825\×(x-\frac{2}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Block ratio now do not generate electricity, do not do to consider;

Wherein, parameter meaning is as follows: the rent on roof is m, and roof is long is a, and wide is b; Single photovoltaic panel area is long is k, and wide is t; Single photovoltaic module cost is n, single photovoltaic module be in optimum angle of incidence and shadow-free blocks time annual generated energy be Q _max; The inclination angle of photovoltaic arrays is α, and the block ratio of front-seat photovoltaic module to rear row's photovoltaic module is x; Photovoltaic module battery row is s; The cost of every kilowatt hour generated energy is y; η _αfor the generated energy Q under unobstructed different angle and the generated energy Q under unobstructed optimum angle of incidence _maxbetween ratio;

The by-pass diode of each photovoltaic module is provided with 3, and in assembly, every block battery is all be in perfect condition.The roof side of being flat-top.

The optimum angle of incidence of single photovoltaic module, adopts " solar radiation calculation procedure " to calculate optimum angle of incidence.Shanghai University Of Electric Power's software adopts C language to work out by Shanghai University Of Electric Power, is suitable as photovoltaic generating system designing and calculating aid.

Be described below in conjunction with two embodiments:

Represent Shanghai for Yangtze River Delta Area, single photovoltaic module optimum angle of incidence sees the following form, and gets 22 °;

Following table is the single photovoltaic module optimum angle of incidence statistical form of District of Shanghai:

η _αsee Fig. 2, and approximate meet function η _α=-8.65 × 10 ^-5× (α-22) ²+ 1;

Therefore, for the optimum angle of incidence of plural number row photovoltaic module, the cost y of every kilowatt hour generated energy can be listed and block the relational expression of ratio x and inclination alpha:

Block ratio $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×[(-8.65\×10^{-5})\×{(\mathrm{\α}-22)}^2+1]};$

Block ratio

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×(1.0825-0.825x\×s)\×[(-8.65\×10^{-5})\×{(\mathrm{\α}-22)}^2+1]};$

Block ratio $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×[(-8.65\×10^{-5})\×{(\mathrm{\α}-22)}^2+1]};$

Block ratio

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×[0.7175-0.775\×(x-\frac{1}{3})\×s]\×[(-8.65\×10^{-5})\×{(\mathrm{\α}-22)}^2+1]};$

Block ratio

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×[(-8.65\×10^{-5})\×{(\mathrm{\α}-22)}^2+1]};$

Block ratio

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33[0.4125-0.825\×(x-\frac{2}{3})\×s]\×[(-8.65\×10^{-5}){(\mathrm{\α}-22)}^2+1]}.$

We select this roof of Fig. 3 as case, and Fig. 3 is roof, Hohai University, Changzhou library, can completion roof, and making long is 13400mm, and wide is 45850mm.

We select Trina Solar TSM-250P05A photovoltaic module as calculating sample, and power is 250W.The wide 992mm of the long 1650mm of this photovoltaic module, cell number is 6 × 9 pieces.Price is 1075 yuan, support price 200 yuan.Suppose that roof rent is 300 yuan of/square metre of years.

Therefore, when computing time is 20 years:

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{3193020\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

Get the then cost minimization y when α=8 ° as can be seen from Table 1 _min=1.258956385 yuan/kilowatt hour.

Inclination alpha/°	Often spend electric cost/unit	Inclination alpha/°	Often spend electric cost/unit
				0	1.280006305	45	1.779679031
1	1.2752369	46	1.817675346
				2	1.271091657	47	1.857999028
3	1.26756232	48	1.900818732
				4	1.264641955	49	1.946320423
5	1.262324925	50	1.994709568
				6	1.260606859	51	2.046213659
7	1.259484639	52	2.101085141
				8	1.258956385	53	2.159604821
9	1.259021451	54	2.22208585
				10	1.259680421	55	2.288878385
11	1.260935116	56	2.360375092
				12	1.262788603	57	2.437017646
13	1.265245216	58	2.519304458
				14	1.26831057	59	2.607799909
15	1.271991599	60	2.703145439
				16	1.276296584	61	2.806072935
17	1.2812352	62	2.917421009
				18	1.286818561	63	3.038154894

19	1.29305928	64	3.169390954
				20	1.299971532	65	3.312427095
21	1.307571131	66	3.46878079
				22	1.315875606	67	3.640237054
23	1.324904303	68	3.828909523
				24	1.334678484	69	4.037319018
25	1.345221445	70	4.268495717
				26	1.356558647	71	4.526113619
27	1.36871786	72	4.814669902
				28	1.381729325	73	5.13972762
29	1.395625934	74	5.508249492
				30	1.410443425	75	5.929065296
31	1.426220611	76	6.413539663
				32	1.442999619	77	6.976548218
33	1.460826169	78	7.637941943
				34	1.47974988	79	8.424810468
35	1.499824607	80	9.37510358
				36	1.521108828	81	10.54366738
37	1.543666064	82	12.01280791
				38	1.567565362	83	13.91190993
39	1.592881825	84	16.45667498
				40	1.619697216	85	20.03544633
41	1.648100634	86	25.42502246
				42	1.678189279	87	34.43809992
43	1.710069314	88	52.5130484
				44	1.743856846	89	106.842345

Table 1 blocks ratio time, system inclination angle with often spend electric cost relation table

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{3193020\×\cos \mathrm{\α}\×(1.0825-7.425x)\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

$y_x=\frac{2070405.56\×\cos \mathrm{\α}+2327715}{3193020\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]\×{(1.0825-7.425x)}^2};$

Visible, when x increases, y increases, so should get therefore, its result should be identical with table 1, the cost minimization y when α=8 ° _min=1.258956385 yuan/kilowatt hour.

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{2043520\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

Get then as can be seen from Table 2, when α=9 °, y _min=1.3507984 yuan/kilowatt hour.

Inclination alpha/°	Often spend electric cost/unit	Inclination alpha/°	Often spend electric cost/unit
				0	1.373862371	45	1.891629738
1	1.368736486	46	1.931193358
				2	1.364267087	47	1.973178377
3	1.360445418	48	2.017759755
				4	1.35726411	49	2.0651304
5	1.354717142	50	2.115503437
				6	1.352799825	51	2.169114823
7	1.351508773	52	2.226226384
				8	1.350841899	53	2.287129346
9	1.3507984	54	2.352148455
				10	1.351378762	55	2.421646819
11	1.35258476	56	2.496031599
				12	1.354419471	57	2.575760746
13	1.356887291	58	2.661351011
				14	1.359993958	59	2.75338751
15	1.363746579	60	2.852535208
				16	1.36815367	61	2.959552793
17	1.373225196	62	3.075309537
				18	1.378972624	63	3.200805911
19	1.385408982	64	3.337198975
				20	1.392548924	65	3.485833876
21	1.400408807	66	3.648283249
				22	1.409006779	67	3.826396902
23	1.418362873	68	4.022365099
				24	1.428499116	69	4.238799937
25	1.439439653	70	4.478841179
				26	1.451210876	71	4.746295553
27	1.46384158	72	5.045822526
				28	1.477363126	73	5.383185714
29	1.49180963	74	5.765598631
				30	1.507218167	75	6.202208828
31	1.523629001	76	6.704789628
				32	1.541085841	77	7.28875124
33	1.559636129	78	7.974657586
				34	1.579331348	79	8.790570683
35	1.600227388	80	9.775801894
				36	1.622384928	81	10.98716431
37	1.645869887	82	12.50991484
				38	1.670753916	83	14.47807569
39	1.697114951	84	17.11507811
				40	1.725037837	85	20.82317953
41	1.75461503	86	26.4070078

42	1.785947389	87	35.74419618
				43	1.819145071	88	54.467927
44	1.854328544	89	110.7447463

Table 2 blocks ratio time, system inclination angle with often spend electric cost relation table

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{2043520\×\cos \mathrm{\α}\×(3.0425-6.975x)\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

$y_x=\frac{1944926.44\×\cos \mathrm{\α}+14463735}{2043520\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]\×{(3.0425-6.975x)}^2};$

Visible, when x increases, y increases, so should get its result should be identical with table 2, when α=9 °, and y _min=1.3507984 yuan/kilowatt hour.

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{1053696.6\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

Get then as can be seen from Table 3, when α=9 °, y _min=1.424211125 yuan/kilowatt hour.

Inclination alpha/°	Often spend electric cost/unit	Inclination alpha/°	Often spend electric cost/unit
				0	1.45008035	45	1.944217782
1	1.444650994	46	1.98253536
				2	1.439876594	47	2.023192348
3	1.435748208	48	2.066356295
				4	1.432258253	49	2.112211914
5	1.429400472	50	2.16096324
				6	1.427169911	51	2.21283613
7	1.425562895	52	2.268081157
				8	1.424577015	53	2.326976982
9	1.424211125	54	2.389834287
				10	1.424465333	55	2.457000388
11	1.425341008	56	2.528864673
				12	1.426840789	57	2.605865022
13	1.428968601	58	2.688495453
				14	1.431729674	59	2.77731524
15	1.435130571	60	2.872959869
				16	1.439179223	61	2.976154275
17	1.443884972	62	3.087728914
				18	1.449258613	63	3.208639424
19	1.455312454	64	3.339990841
				20	1.46206038	65	3.483067634

21	1.469517924	66	3.639371267
				22	1.477702347	67	3.810667583
23	1.486632735	68	3.999047135
				24	1.496330097	69	4.207002775
25	1.506817485	70	4.437530555
				26	1.518120119	71	4.69426253
27	1.530265533	72	4.981643869
				28	1.543283732	73	5.305172531
29	1.557207371	74	5.671728877
				30	1.572071952	75	6.090037203
31	1.587916043	76	6.571325168
				32	1.604781523	77	7.130287671
33	1.622713852	78	7.786532819
				34	1.641762377	79	8.566816753
35	1.661980665	80	9.508619595
				36	1.683426885	81	10.66610562
37	1.706164229	82	12.12055389
				38	1.73026138	83	13.99972994
39	1.755793048	84	16.51662965
				40	1.78284056	85	20.05471674
41	1.811492536	86	25.38101761
				42	1.841845637	87	34.28540791
43	1.87400543	88	52.137762
				44	1.908087344	89	105.7880071

Table 3 blocks ratio time, system inclination angle with often spend electric cost relation table

Blocking ratio is $y=\frac{3678000\×(1-x)+278842.5\×\cos \mathrm{\α}}{1053696.6\×\cos \mathrm{\α}\×(5.3625-7.425x)\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]};$

$y_x=\frac{2070405.56.56\×\cos \mathrm{\α}+7585875}{1053696.6\×\cos \mathrm{\α}\×[-8.65\×10^{-5}\×{(\mathrm{\α}-22)}^2+1]\×{(5.3625-7.425x)}^2}$

Visible, when x increases, y increases, so should get its result should be identical with table 3, when α=9 °, and y _min=1.424211125 yuan/kilowatt hour.

In sum, be 8 ° when getting inclination angle, and make to block ratio and be time often spend electricity cost minimum, now the spacing of front and rear row photovoltaic module is 1.71m.

The present invention is when considering many factors, the optimum angle of incidence method for designing of a kind of roof distributed photovoltaic system of proposition; Output energy cost is minimum when ensureing photovoltaic system per kilowatt, the optimum angle of incidence of single plural number row photovoltaic module being calculated, the inclination angle of the best can be installed according to actual conditions, improve the generating efficiency of photovoltaic system.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.

Claims (2)

1. the optimum angle of incidence computing method of a roof distributed photovoltaic system, comprise the optimum angle of incidence of single photovoltaic module and the optimum angle of incidence of plural number row photovoltaic module, it is characterized in that: the optimum angle of incidence of described plural number row photovoltaic module, its computing formula distributes as follows according to the ratio that blocks of front-seat photovoltaic module to rear row's photovoltaic module:

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×(1.0825-0.825x\×s)\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.64\×[0.7175-0.775\×(x-\frac{1}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is $y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33\×{\mathrm{\η}}_{\mathrm{\α}}};$

Blocking ratio is

$y=\frac{m+\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×n}{\frac{b}{t}\×\frac{a}{\frac{k}{\cos \mathrm{\α}}(1-x)}\×Q_{\max }\×0.33[0.4125-0.825\×(x-\frac{2}{3})\×s]\×{\mathrm{\η}}_{\mathrm{\α}}};$

Block ratio now do not generate electricity, do not do to consider;

Wherein, parameter meaning is as follows: the rent on roof is m, and roof is long is a, and wide is b; Single photovoltaic panel area is long is k, and wide is t; Single photovoltaic module cost is n, single photovoltaic module be in optimum angle of incidence and shadow-free blocks time annual generated energy be Q _max; The inclination angle of photovoltaic arrays is α, and the block ratio of front-seat photovoltaic module to rear row's photovoltaic module is x; Photovoltaic module battery row is s; The cost of every kilowatt hour generated energy is y; η _αfor the generated energy Q under unobstructed different angle and the generated energy Q under unobstructed optimum angle of incidence _maxbetween ratio;

The by-pass diode of each described photovoltaic module is provided with 3; The described roof side of being flat-top; In described assembly, every block battery is all be in perfect condition.

2. the optimum angle of incidence computing method of a kind of roof according to claim 1 distributed photovoltaic system, is characterized in that: the optimum angle of incidence of described single photovoltaic module, adopt " solar radiation calculation procedure " to calculate optimum angle of incidence.