Heating greenhouses with solar energy - new trends and developments Grafiadellis M., Traka-Mavrona E. in

Heating greenhouses with solar energy - new trends and developments

Grafiadellis M., Traka-Mavrona E.

in

Choukr-Allah R. (ed.).

Protected cultivation in the Mediterranean region Paris : CIHEAM / IAV Hassan II

Cahiers Options Méditerranéennes; n. 31 1999

pages 119-134

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--- Grafiadellis M., Traka-Mavrona E. H eatin g green h ou ses with solar en ergy - n ew tren ds an d developmen ts. In : Choukr-Allah R. (ed.). Protected cultivation in the Mediterranean region . Paris : CIHEAM / IAV Hassan II, 1999. p. 119-134 (Cahiers Options Méditerranéennes; n. 31)

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-

NEW

Ì. and E.

-

Thessaloniki

-

Abstract: The last two the

to study the possibilities of

of of

the the system on the top of the

the by of the in the

Japan the - heat exchange system found Today many

on the of the efficiency of the

which has to the the study of the of

on the modifications of to

this the

discussed.

a expansion of the plastic in

been noticed. unheated simple

plastics sheets, which make use of the

sky.

night the minimum to than the accepted levels and the

the

of the of

adaptation to the of

compensated to a the day

1984). is widely known that

yield and quality of the that in the

the plants and on the

application of

beneficial, but in many cases it has found to be uneconomical 1989).

The this the

-

the low light

the the the simple

to the

the such as the double

the the use of films, the establishment of

the the

the to the conclusion that although each technique is

1-2°C the minimum the

the joint effect of two to be the unheated plastics

Cahiers options vol31 119

is not enough heat in the and in the soil to be used at

OF

The of the scientists to use the The

the

the

the the the scientists lefi the

the 20th the the same level as it was in the

time of the oil of 1973 a lot of

to

fact that the is a huge the scientists to find out ways of using the heat wasted by ventilation 1990;

the as

1984) the

in the U.S.A. a

in daytime was heated by plastics in the in the

et al., 1978).

et al. (1 978) USA the

the cold seasons to heat a

(1 978) has designed a a of the

incoming the at night by the the

the the

in to collect and the

(1980) tube

and the collection at at night of

in the

Japan the collection and

(1986) system, which was doing use of a double the collection of

at the of the

the USA a bench

-

system has been designed with

which at daytime a fan the to at night the flow was

et al., 1978).

Leva1 and Zamir (1987) in in daytime the

excess fiom the in to be used in the night.

vol.31 120

as well as Yamamoto (1973)

of using the as a means the daytime to be used at

night.

(1987) in Tunisia has studied a mulch system of black tubes laid on the soil of the

at night.

of the top of the

simultaneously the to heat fiom the

(1991) on behalf of the technical and

economical aspects of the

the that the

the

-

bed system, the

-

heat exchange system and the flat plate

plastics belong, found also to

the that the in

which the passive system and the on the

capital can be the

(Table 1).

Table 1: Technical and e ~ ~ ~ ~ r r m i c d characteristics of the main solar systems introduced into the greenhouses.

of of gained Cost per m2 of

oil ($)

($1

With 4

-

5OC 12

-

15 6.499 3.519

The

-

heat exchange 5 ^*

soc

8 - 10 17.812 6.400 system

10

-

²⁵

-

30 40.624 15.625

on the

-

5% 10 542 298

The

-

⁵

- soc

⁸ -10 16.750 6.03 1

4

-

5OC 8 -<l0 494 494

-

^12OC 15 30.000 10.759

pumps 1 ooc 15 5 1.250 19.375

OF

is

the using a fan by means

(passive systems).

The advantages of the active systems the placement of the heat, the the high efficiency. The disadvantages of these systems the high cost, the need of

to fans pumps and the complexity.

Cahiers options ~01.31 121

The passive the

than can the active systems fail

et al., of the passive systems

the little the difficulty to the collection and facilities into the

One of the on using passive the

that of (1967) in the Using with

low that daily of the

El-Aidy in his thesis the he did in the

as to

in

(1984) has studied the effect on the

of cantaloupe F1 that the tubes in

to the

(1984) is to

-

bed

30cm deep that the that heat collection efficiency is not adequate

since the of heat the mainly by slow.

(1983) have investigated the efficiency of of

film located on an insulated plate and found that

the on an in and 10mjlm21day in

August.

the Woolston (1985) used in Finland as

tubes

and that able to

of down to 4.2OC.

(1 98 1) is to the use of some simple means of passive heating applied to the

One successfbl attempt to use a passive

at in (Fulley, 1990).

All the of the above mentioned scientists did not find any application in the the time.

Cahiers Options voL31 122

ON SOE

TUBES OF

is the

The in

in 1977 and until 1983 1984). The

1978. The success of these tests was limited due to to

the of the scientists in

algae development in an

when the passive its

l m a 75ì thickness and

a lot of

the follows:

. as

the the lowest cost

and it was suggested the most suitable the the

al., 1990).

(80, 90, 100, 110,

120cm), it was found that the one of lOOcm

.

that minimum

the

of a collection

-

(a day)

the tubes at the beginning of the cycle, the amount of

the insufficient amounts

at the

day and night a negative balance

the

200, 225 and

that tubes of 100-125 W

the if fiom

et al., 1988).

that as a

the effect on 1, to

total to

Cahiers Options vok!31

Figure 1. Arrangement of the passive solar system in a greenhouse.

that the

collected with the in to

16.016-18.280 of gas oil and that from the the

18-19%

of studying the effect of the passive system on the minimum that when in the

0.75"C, in the

6.08"C and in the

with a single sheet of was 4.70"C was also that the

passive system at humidity by 6-

the

at midday in the plant level by about 15% and in the by

by that

by the the of the tubes in the quantity of 4g 85

an the efficiency of the passive system by 25% was obtained.

the of

found that a big the of the tubes, the

CuSO4 in the quantity of the of the efficiency (25%) has given.

Cahiers Options 124

=section

water tubes

Figure 2. Cross section and details of establishing the passive solar system.

Figure 3. Arrangement ofthe water tubes in horizontal position along a greenhouse.

passage

Figure 4. Other way.of arranging the passive solar system in a greenhouse.

vo1.31 125

was also found that tubes in position (Fig. 5) effective in collecting the the tubes is that of 60cm and by adding black the an of 38% of the efficiency of this system is obtained

it was found that the passive system with tubes of l m

the 35% of the soil the

in a

of the

water tubes

Figure 5. The passive solar system with the water in vertical position in the sides of a greenhouse

a study of the effect of heating systems on the

-

et al. (1992), it was found that the

the the second one heated by the

and quipped additionally with the passive the total

by 37 the by 45

to the the it was also

that the the total an in the

mean size, while the the of

tomatoes.

199..), when the passive the total

on of 16 tomato to the gas and the

this case the the two

Cahiers Options 126

of the a as

was found that the total the two the

system and with the to the nonheated

1998).

the quality was studied

-

^1993). the that in the

the

-

weight The mean h i t

weight of the gas oil the

the the gas oil

soluble and total solids of the juice, but also the blossom

-

end incidence. The the juice had a tendency to as the

An 1992 in the

-

199..), the tomato set of six two lines

as affected by the the passive to the conventional

heating with the gas oil and the gas oil

it have been found that by the application of heating by the passive system the the wgight of individual

of the as the in the

and the the

heating systems.

an of studying the effect of plant defoliation and the

of the passive system, it was found that by the mean

weight, the soluble solids, the the the the

not affected and that the the total soluble solids in the

two the the et al., 1993).

The effect of the tubes in combination with soil mulching by miky polyethylene film on the fiuit yield of and no LSL)

-

et al., 1996). Soil mulching by milky polyethylene film by 12%, 19%, total yield by 18% and mean fiuit weight by 9%.

(1998) in the of

was found that by the application of the passive system in low tunnels an minimum by 3-4" was noticed, the

fiuits, of 54.6% 10 days

institutions and the the that in

the

it is not possible to obtain an acceptable minimum of 12-13°C.

So an additional heating system with conventional fuel is 1987).

of its low cost, its .climatic the

its effect on the and total

the can

the 30-100% 1989; et al., 1990;

1991).

127

ON

1986, in the

-

in Thessaloniki, it was

a joint in 1 the use of the

The of at

in

by Odysseos in that in a the

passive the leaves of the plants was by that of

the that the plants. the same

of light intensity by 30-40% close to the

in many to 70% in the was also found that this

system is keeping in daytime the maximum au at than the found that

the suitable in less developed plants, the efficiency of this

system is in obtained

with as much as possible tubes and the application of the tubes in the long sides of the is highly suggested.

in that the of

system was 8-20%, the by at

maximum the day by

the that the application of this

the suitable to as to 45%

the

that in

the efficiency of low. They also mentioning

that a than a tube next to it and fully filled

that a it as well as

(3 1% vs 43%).

(1 that

has shown that a tube, which was not shaded by plants, collected twice as much

heat than one that was shaded by day by the tubes

to

in 2 lcm of the

soil obtained 1-2"C

et al. that B

a that by using the passive

system in a an the minimum of 24OC

in to the

128

a it that with the application of

the passive the minimum 6.3'6

in the ambient and also that in the

system was installed in to the the

that the heat exchange between tubes and

can be the equation: Q=281 ta and tw the

the tubes and the connective coefficient of the tubes is 5.3

w/"c/m

data collected in the it has been that the adoption of

the passive cultivation the income of the

the analysis of the et al. (1990) have shown that by the application of the

system in the the income of the is 30% in tomato and 50% in

Almost all the the passive

in 1986 in behalf of the joint

At the scientists in in to

the efficiency of the passive system and adapt it to

tests and investigations by plastics

to the to the of plastic tubes.

The last the the

big

on the the need of adding to the

with conventional fuel, insulating the the

tubes, etc.

The last 4-5 the of the

Community is

all the the

the passive

became the all

the the fuel the obliged to

attention into the use to the heating

the systems developed, the passive system is gaining

the the its simplicity, low cost

and high efficiency on the use

All the investigations and applications of the that with

this system it is not possible to the it can

when the main heating systems failing and also can the

vol31 129

fuel consumption. the the of the not

heated, the passive system is the

the this the

the the income of the

Although the passive its way of acting is the

is needed on the following topics:

l. the quality of the plastics tubes.

Study of the to the CuS04 into

the

3. Study of the effect of this system on condensation on the

4. on the wall of the in to the

which is falling on the

5. this system on the in

6. Study of how the insulation techniques of

affecting the efficiency of the passive system.

Study of the of to the passive

conditions.

8. Study of the of the the plants to avoid

shading on the

Airhart, 1984. 148:

785-789.

1981. heating applied to 1 1 5 :

543-551.

Amor Ben Salhi, Zid ben A. and Verlodt, 1990. of by a passive system in Gafsa (southwest of 263: 131-138.

Baille, A., 1988.

FAO : 107-

116.

Baille, A. and Th. Boulard, 1986. An of

to the 2nd FAO ThesSalodi,

Baille, A. and Th. Boulard, 1987. in FAO

130

Bouam, Gerasopoulos, Grafiadelk, 1998. The effect of the passive heating

system and of the in low

in Oct. 6-9, 1996.

Boulard, Th. and A. Baille, 1986. of to the 2nd FAO

Castilla N., Tognoni, F. and C. Olympios, 1992.

of

J., 1978. sun 18 1

-

184.

E., 1996. The passive system placed in the sides of the Sci.

Esquira, Segal, and A. Antler, 1988. heating of

of in of FAO

Fulley, 1990.

of Ganoli, 1989.

6arzolii, and Shell, 1984. an

Grafiadellds, 1984. of

223-232.

6rafiadellk3, 1987.

Grafiadellis, 1990. The use of

Gmfìadelli9, 1991. of technical and economical aspects of eight systems used

in on

GrafiadeUis, and S. 1980.

553-560.

Grdiadellis, Spanomitsios, G. and 1988.

of 21 : 21-24.

Grafiadellis, Spanomitsíos, G. and 1990. the

VOMI 131

Grafiadellis, and F. Taieb, 1998. Cooling effect of the passive system in (in

Grafiadellis, Traka

-

E., E. and G. Spanomitsios, 199.. of the passive system on the

199 1.

J.J., 1991. on special to

G., 1984. sulla del

melone in 4:

Jelinkova, 1988. system in

-

and Akadeniz, 1988. of

with classical ones. of FAO 21: 65-66.

E., 1984.

56 1-566.

Zamir, 1987.

157-162.

Nara, and Sabrai, 1983. The efficiency of the

and E. Papanagiotou, 1991. Economic consequences of the system of heating on the of

P.F., 1992. The influence of the

and Gdiadellis, 1989. Assessing income benefits in is

Grafiadellis, Papanagiotou, E. and 1990. Evaluating the effectiveness of the

Grafiadellis, and E. Papanagiotou, 1991. Economic consequences of the system of heating on the of

G. and S.

of the

of FAO.

S. Soil

-

^{FAO RE;uR} Technical

150-1 53.

E., Grafiadellis, and E. Traka

-

A Study of the techniques

the efficiency of the passive XXV

Cahiers

W.J. and J.C. Simkins, 1978. of a heating

and A.F.

in

O., Serrano. and A. Anton, 1988. The use of passive sleeves in 21 : 3 1-33.

A. Use of passive heating system to

Nisen, A., Grafiadellis, Jimener, P.F., A., Verlodt,

Villele, O., Zabeltiiq W.O. Boudoin, 1990.

the of

313.

Odysseos, G., 1988. the

of light on

Pavlou, G., 1991. Evaluation of filled polyethylene tubes used passive

Photiades, 1989. of on tube heating

30: 9-12.

Photiades, tubes. FAO

104-105.

W.J., Parsons, Bartok, J.W. and Aldrich, 1978.

heating

pond as an

Sondern, J.A., 1967. the in tunnels by means of the accumulating effect of a

Stanghellini, 1992. to

conditions. Acta

Taieb, F. and Grafiadellis, 1993. of the efficiency of the passive heating

Technologies in the Field of in 161-

169.

Takakura, T. and Nishma, 1980. and

Cahiers vol31 133

Traka

-

^E., Bletsos, F., Grafiadellis, and G. Spanomitsios, 1993. The effect of quality.

of

-

and Technology, Chania,

Traka

-

E., Bletsos, F., Graiiadellis, and G. Spanomitsios, 199.. Tomato’fiuit set

at 1st

Traka

-

^E., Grafiadellis, Paraskevopoulou

-

Paroussi, G., and G.

Spanomitsios, 1992. The effect of the

of 855-870

Traka

-

E., Grafiadellis, and 1995. of to

Traka

-

E., Spanomitsios G. and F. Bletsos, 1996. Effect of mulching and of adding the the plastics tubes of the passive system on the of

of 293-296.

Verlodt, 1987.

179-181.

A. le chauffage passif des Acta

Woolston, S., 1985. of Finnish at

Yamamoto, Y., 1973. an eaith

-

heat

J.

Zabeltitz, von Chr., 1987.

13-21.

zabeltitz, von Chr., 1988. of FAO

: 9-1 1.

Cahiers vol31 134