WO2001045179A1

WO2001045179A1 - System and method for collecting solar energy

Info

Publication number: WO2001045179A1
Application number: PCT/NL2000/000917
Authority: WO
Inventors: Jan Wanner
Original assignee: Mastervolt Solar B.V.
Priority date: 1999-12-16
Filing date: 2000-12-14
Publication date: 2001-06-21
Also published as: AU3242401A; NL1013874C2

Abstract

A system for collecting solar energy and converting it into electric energy at a location near a space to which persons have access, for the purpose of supplying said electric energy to the electricity grid that is present. The system comprises a panel (1) that is disposed in the outside air, which panel (1) collects sunlight and converts it into direct current, an inverter (7), which converts said direct current into alternating current, and an electric connecting cable (6) for transporting said direct current from the panel (1) to the inverter (7). The connecting cable (6) thereby extends from the outside to the inside of the space, and the inverter (7) is disposed inside said space.

Description

SYSTEM AND METHOD FOR COLLECTING SOLAR ENERGY

The invention relates to a system for collecting solar energy and converting it into electric energy at a location near a space to which persons have access, for the purpose of supplying said electric energy to the electricity grid that is present in the space in question, comprising a panel that is disposed in the outside air, which panel collects sunlight and converts it into direct current, an inverter, which converts said direct current into alternating current, and an electric connecting cable for transporting said direct current from the panel to the inverter.

A system of this kind can be used for supplying a building in which the space in question is present with electric energy, but also for supplying the collected energy to the network via which electric energy is transported to the space in question, and possibly to other buildings. The direct current from the panel is thereby converted into alternating current by means of the inverter, which alternating current corresponds to the alternating current that is normally used in the building, for example 220 Volt and 50 Hertz.

It is usual to mount the inverter near the panel or on the panel, so that the usable alternating current is directly available from the panel/inverter unit. The energy to be delivered by several panels/inverters can thereby be carried off as directly usable alternating current via a cable that extends along the inverters .

The inverter can be mounted on the rear side of the panel, so that on the one hand it does not obstruct incident sunlight, whilst on the other hand the inverter is more or less sheltered. Nevertheless it is necessary to make the inverter waterproof or splashproof .

In addition, the inverter must be capable of withstanding relatively large temperature fluctuations, not only the normal temperature fluctuations that occur in the outside air, but also the relatively high temperatures to which the panel may heat up, also on the rear side. In practice these temperatures may rise as high as 70 °C.

Another drawback of mounting the inverter behind the panel or under the panel is the fact that this makes access to the inverter difficult. Not only because the amount of space behind the panel is often limited, but also because the panel is often installed at a high location, for example on the roof of the building.

The object of the invention is to provide a system for collecting solar energy and converting it into electric energy, which system can be of cheaper and/or simpler construction and which enables easier maintenance.

According to the invention the inverter is to this end disposed inside the space rather than outside, and the connecting cable extends from the outside to the inside of the space. The panel and the connecting cable, through which a relatively low voltage direct current is transported, are the only parts of the system that are disposed in the outside air, whilst the inverter and the part of the system in which a higher AC voltage is present are disposed inside the building, at a location thefefore where the demands that are made on the protection of the parts are much less exacting.

In preferred embodiments several panels are connected to the inverter via one common connecting cable, or several panels are each connected to an inverter via a connecting cable.

Preferably, the inverter is disposed in a room of a building to which persons have access, so that the invertor is easy of access for maintenance and the like activities.

Since the inverter is disposed inside the building, the inverter need not be made waterproof or splashproof, and the inverter will not be exposed to extreme temperature fluctuations or high temperatures . This makes it possible to make the inverter much smaller and of much simpler construction, in particular if the inverter converts direct current into alternating current for only one panel. Preferably, the inverter is connected to a plug that can be inserted into a wall socket that is present inside the space. It is readily possible thereby to integrate the inverter in the plug, so that a combined plug/inverter is obtained, as is known with adapters for electrical appliances, wherein the adapter is provided with a plug that can be inserted into a wall socket .

Preferably, the inverter is therefore incorporated in a plug that can be inserted into a wall socket that is present in the building. This can be considered to constitute an invention by itself.

Also preferably, the connecting cable is connected to the inverter in such a manner that it can be manually detached therefrom, so that the user can easily replace the inverter or have it repaired if it is broken.

Preferably, the housing of the inverter is not waterproof, which enables lower-cost production.

Especially advantageous is thereby the fact that it is possible to provide the housing with holes for air cooling of the electronic components.

In one preferred embodiment the inverter includes an indicator which indicates whether the inverter is operating, which indicator may consist of a display, or a light or other light-emitting element in or on the inverter. Such an indicator can be used advantageously because the inverter can be fitted at a location that is exposed to view, with the added psychological advantage that the user can see when he is saving expenses as a result of the fact that electricity is being supplied by the solar panel .

The use of an indicator in an inverter for the system described in the introduction can likewise be considered to constitute a separate invention.

The invention furthermore relates to a device for collecting solar energy and converting it into electric energy, comprising a panel which is capable of collecting sunlight and of converting it into direct current, an inverter which is capable of converting said direct current into alternating current, and an electric connecting cable for transporting said direct current from the panel to the inverter, wherein the inverter is connected to a plug which can be inserted into a wall socket .

The invention also relates to a method for collecting solar energy and converting it into electric energy at a location near a space to which persons have access, wherein a panel that is disposed in the outside air collects sunlight and converts it into direct current, wherein an electric connecting cable transports said direct current from the panel to an inverter, which converts said direct current into alternating current, wherein said connecting cable transports said direct current from outside the space to inside the space where the inverter is disposed.

The invention furthermore relates to a method for installing a system for collecting solar energy and converting it into electric energy, wherein a panel is disposed in the outside air, which panel collects sunlight and converts it into direct current, wherein an inverter, which converts said direct current into alternating current, and an electric connecting cable for transporting said direct current from the panel to the inverter are fitted, characterized in that said inverter is disposed inside a space to which persons have access, and in that the connecting cable is fitted between the panel disposed outside said space and the inverter disposed inside said space.

The invention relates in particular to the use of panels having a power output of up to 150 W, with the direct current being supplied having a voltage of maximally 50 V.

In order to explain the invention more fully, an exemplary embodiment of a system for collecting solar energy will be described hereafter with reference to the drawing.

Figure 1 shows a conventional system; and Figure 2 shows a system according to the invention.

The figures are merely simplified and schematic representations of an exemplary embodiment .

Figure 1 shows a conventional device, which is sometimes called "AC module" to indicate that it is a unit which delivers alternating current. Said alternating current is obtained in that panel 1, which comprises solar cells on its front side, collects sunlight, which sunlight is converted into direct current by the solar cells. The figure shows the rear side of the panel 1, and an inverter 2 is mounted on said rear side.

The direct current is led directly from the panel into the inverter via a connecting cable (not shown) . To this end the inverter can be mounted on the panel at the location where the connecting cable exits panel 1, but it is also possible to use a longer connecting cable, which can be connected between said place of exit and the input of the inverter, so that the inverter can be disposed some distance away from panel 1.

According to Figure 1 an outgoing connecting cable 3 is connected to inverter 2, which cable carries off the alternating current from the inverter 2 , for example to a socket in the building to which the panel is fixed. A plug 4 is attached to the connecting cable for that purpose, which plug can be inserted into said socket.

In this way the collected solar energy can be supplied directly to the electricity grid that supplies the building in question with power.

A few drawbacks of this system are the fact that the inverter must be waterproof, the large temperature fluctuations and the high temperature around the inverter, the poor accessibility of the inverter when maintenance work is required, the higher installation costs, owing to the fact that more than just a flat panel must be installed on the roof of a building, and the safety requirements which the system components are to meet, also those components in which the alternating current voltage is relatively high.

Figure 2 shows a system according to the invention. Also this figure shows the rear side of the panel 1. Extending from output 5 of panel 1 is a connecting cable 6, which may be as long as is needed to extend to the inside of the building to which the panel is fixed. Present at the end of connecting cable 6 is an integrated combination 7 of an inverter and a plug, which are accommodated in a common housing.

The housing of the combined plug/inverter 7 is provided with an indicator 8, which indicates whether electric current is being delivered by the system.

Since the inverter is disposed within a building, it can be made smaller and of simpler construction, thus enabling integration with a plug.

The illustrated embodiment is merely an example, also other embodiments are possible.

Claims

1. A system for collecting solar energy and converting it into electric energy at a location near a space to which persons have access, in particular for the purpose of supplying said electric energy to the electricity grid that is present, comprising a panel (1) that is disposed in the outside air, which panel (1) collects sunlight and converts it into direct current, an inverter (7) , which converts said direct current into alternating current, and an electric connecting cable (6) for transporting said direct current from the panel (1) to the inverter (7) , wherein the connecting cable (6) extends from the outside to the inside of the space, and wherein the inverter (7) is disposed inside said space.

2. A system according to claim 1, characterized in that several panels (1) are connected to the inverter (7) via one common connecting cable (6) .

3. A system according to claim 1, characterized in that several panels (1) are each connected to an inverter (7) via a connecting cable (6) .

4. A system according to any one of the preceding claims, characterized in that the space to which persons have access comprises a room of a building.

A system according to any one of the preceding claims, characterized in that the inverter (7) is connected to a plug that can be inserted into a wall socket that is present inside the space.

A system according to claim 5, characterized in that the inverter (7) is incorporated in the plug.

H H H <-0 ∞ -J t H O

€, ω rt rt H- > s- s- Ω Ω H- sS Ω ^•≤ H- ≤ TJ Ω Ω rt > tr Ω Ω Ω 3 . . Ω >

X P' 0 rt U^* tr £ 0 P p- 0 P^J rt ^ Hi x-^> 0 £3- Φ 0 O H-¹ ft) CD H-¹

Φ P ft> 3 H- Φ H P rt H- P ^*-^■- Pi Φ O ft⁾ O 0 ft⁾ O ^*-^■- 3 ft⁾ CD ts " — ft⁾ ω

H{ rt ^*£ H- φ Ω Hi Hj P O Ω <J Ω H- φ rt < H- •<; H¹ rt ^■^ 3 TJ T l-^*- ^ 3 H-

Φ H- tr 2 rt X Φ Φ φ X Φ X P < t) H- 3 CO H- CO tp 0 H-i 3 O Φ H- 3 CD

H- ιp H- H- rt X H- P Ω ft⁾ H rt H- φ Pi O rt P rt rt P H- CQ rt H O CD rt

P ω Ω O O Ω P rt rt ι-^J H- rt H- O Ω Hi Φ Φ IP X φ H- Φ ω - Φ - φ rt X ft⁾ H- rt CQ w- m Φ Pi 3 Φ 3 P P φ 3 rt Ω 3 ft) p. Φ P rt Hi P Φ P Φ rt Ω O rt rt CO Ω t O Ω

P ft⁾ w- TJ l-" l- t H ιp i-i Ω tp Ω x-¹ Hi X ^•s X ft⁾ Hi P^J ft) Φ CQ tr ft⁾ ft) P tr ft⁾

P co Φ Φ o tr Φ 0 P ft) ft⁾ Φ O Φ H- ft⁾ Ω 0 Ω P - ft⁾ ft) Ω rt P PJ Ω φ •t) Hi Ω f-i Φ 3 Ω ft⁾ 13 H- TJ Ω 1^*1 rt Hi Ω rt 0 Ω i Hi Ω φ Hi Ω ι-^J 0 O rt H- ft⁾ rt ft) rt ft⁾ rt H- X 0 X CO 0 Φ ≤ tr ft⁾ 0 I-¹- Ω ft⁾ 0

Φ Ω CD o » Ω H- P rt tr H- tr tr H« Ω P Ω Hi Φ H- Hi Pi t 0 Ω Hi rt ft Ω H

Ω 0 φ P H- o P tr I-¹ P ^*-^■ H- H H- 0 ft⁾ rt Pi P Pi Φ d rt Pi Φ rt rt P Pi CO Ω I—¹ CO Φ Φ φ tQ Φ P φ Ω t-¹ Φ P Φ H- Φ t P- Hi Hi ω Φ H- Ω Pi Φ H-

4 <5 φ i-s ft l-^J Hi Hi P P O Φ H- Hi P ft) Hi P

H- Φ H- φ φ rt T _^^ Ω o O o Φ Φ rt H- H- I Φ H- t H I-¹- P H- tp P ft H- t

Ω Hj P SD P Ω rt Φ ft⁾ CΛ C Hi Hi P Ω Φ P N Ω ω P tp N O N rt < Φ rt Φ ι-i P Hi Pi Φ rt Hi i φ ft rt rt H- Φ rt tr Φ rt

Ω CQ rt Φ H H- P Φ Hi Ω H- Ω »-i x-^>- H- Pi 0 Hi TJ O P rt Ω Pi O Φ rt Pi O

0 X IP P ,-~. X-¹ Hi Φ 0 0 ιp P _^-~ Ω 0 H ω tr 0 X

P H- Φ ft⁾ •- tp H- -J o P P Φ t 1 Φ H-

P Ω P ,— i-i rt < Ω ^*-^■ ^ ft⁾ H- ft) P O Ω rt Φ P H- ft) 3 ft⁾ rt rt P P H- <! ^*-^■ ft⁾ rt P P ft) P P

Φ 0 Ω ft⁾ CO rt H - Φ rt Φ ω O ^■^ Ω H- ft) X ft⁾ •<: P H- "<

Ω (-^*• Φ rt o O H- -— ' rt HJ Ω Ω 0 H¹- H rt Pi H- H-¹ 0 H- rt C P rt ft P rt CQ I-^* fl H ft⁾ rt Ω rt O h-¹ co X 0 Ω φ 3 ft⁾ 0 P tr 0 ft) <J tr 0

H- rt O CO ft⁾ !D ft⁾ rt ft⁾ P H- C H- 3 ft⁾ rt ft⁾ P 0 Pi rt CO H- ft⁾ P h-¹ Φ ft⁾

P 0 H- ^•> Hj Ω 0 3 Pi P P O Hi 0 t rt φ 3 00 H- H- tl rt Φ H< rt Φ in P ≤ 0 CO t H{ IP ^ • ft) T3 ^ ~ 0 P tP •^ ft

Oi Φ z 0 φ ft⁾ P rt *ϋ ft⁾ Φ H- φ Φ rt rt 0 0 H- P tp rt 0 Φ rt 0

Ω H- X Ω P h-¹ X 0 P CO P ω ω P Hi ^ Hi P rt Ω φ X Hi Pi Hi X Hi ft⁾ H{ ft⁾ φ ft⁾ Φ Φ Φ ft) rt H- φ ft⁾ H- Φ Φ 13- ^ H- - H-¹ Φ Φ Φ tr Φ H- H rt ii Ω rt φ H- - P P Hi rt P rt P ft) P CΩ Φ ft rt _^^ rt

Ω Hi Φ H- IP O ft H- H- h-^* P. M ιp IP H- Pi H- X rt t Hi ω Ω H- X ft) i Ω X

Φ rt H- 0 ^•- O Φ t=i Φ ft⁾ H- 0 H- 3 Φ CO 0 PJ H- 3 rt 3 φ Ω 0 Φ

Ω P P Ω Pi IP Ω a ιp ft⁾ IP Ω • X-¹ Ω P. 0 Hi < tr P

. — . Ω O $u Φ rt ⁱ- tf ft) • ft⁾ Φ ^•τi φ rt φ rt 0 Φ TJ Φ H- P TJ

CD £ I-¹ ft) P P Φ rt Hi CO ι-i H- ri^¬ TJ 0 rt H< H< CO Φ P Hi Hj p Φ H{

— Hi I-¹ Φ rt 0 rt ft⁾ H- φ 3 ft⁾ P. Φ rt Φ Hj rt €. H- rt φ Ω Φ

H( φ T3 ft) • Φ H- Ω Ω ft⁾ 3 O Φ Ω H H- X ft⁾ Ω Φ Ω rt CQ rt Ω ft Φ Ω 0 H{ Ω ft⁾ HJ Pi rt Φ P Φ Ω Hi Φ 0 N Φ rt H Φ tr H- φ

Hj 3 rt 3 O M Pi o Pi Hi Φ Φ Pi Φ Ω P Pi ⁾ rt O Φ ft) P T3 — . Pi Ω rt P 00 _^-» H- i O Hj . . H- Hj X tp H-

P - < -J H- d Φ O ,- . < ~j α ft) •rj TJ 0 3 Φ co CO Φ C - — HJ ^i Hi Hi H¹ φ - — t H- H- ft) Hj — tp Hi ft) Ω t

Ό . — . TJ »-i t - Φ ^i Hi Hi 0 Ω O H<

H rt ft⁾

0 0⁾ Ω Φ _^— _^ rt H- φ O 0

Ω H- rt tr t — P -0 H- C0 Hi 3 t-¹ rt Φ P rt P ω φ

IP IP

said direct current from the panel (1) to an inverter (7) , which converts said direct current into alternating current, wherein said connecting cable (6) transports said direct current from outside the space to inside the space where the inverter (7) is disposed.

13. A method for installing a system for collecting solar energy and converting it into electric energy, wherein a panel (1) is disposed in the outside air, which panel (1) collects sunlight and converts it into direct current, wherein an inverter (7) , which converts said direct current into alternating current, and an electric connecting cable (6) for transporting said direct current from the panel (1) to the inverter (7) are fitted, wherein said inverter (7) is disposed inside a space to which persons have access, and wherein the connecting cable (6) is fitted between the panel (1) disposed outside said space and the inverter (7) disposed inside said space.