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Audio-Visual Off Grid Energy options

Powering Audio-Visual Equipment in Rural Areas

Communication, entertainment and information are as critical for rural living as they are for urban living. Access to modern communication, information and entertainment media makes rural lives more productive and comfortable. As rural people increasingly demand these services, there is correspondingly rapid growth in demand for audio-visual equipment in off-grid rural areas. Today rural projects, businesses, schools and a growing number of households make daily use of audio-visual equipment (radios, televisions, videos, mobile phones, etc.). There are a range of energy sources, including renewable energy sources, that can provide power for them. The range of services are wide: they could be as crucial as a 2-way radio link between a remote clinic and an urban hospital, or a computer for a rural NGO office, or as simple as a radio cassette player used in a household for entertainment.

Audio-visual appliances share a need for electric power. When the appliance is larger than a radio or cassette player, supplying it with power in off-grid areas is often a major challenge. Low cost PV systems have greatly expanded the variety of equipment that can economically be powered off-grid, but planners still need to be aware of what they are buying beforehand to avoid costly mistakes. It is common for groups to start up operations in an off-grid area with equipment that is inappropriate for the power supply capabilities of, for example, a small PV system. In such cases, they are forced to spend much more on energy supply equipment than they expected. Such situations can be avoided by advance consultation with appliance and energy equipment suppliers, and by using this guidebook.

1.0 Audio-visual Considerations: Think About Your Power Requirements Before Purchasing Your Off-Grid Appliances

When powering audio-visual equipment, there are a number of issues that need to be carefully considered in the planning stages. Some of the issues set out in the introductory module are repeated here. Most audio-visual equipment, if selected carefully, can be powered with PV systems in a cost-effective manner.

There are three general categories of audio-visual equipment, which commonly need to be powered in remote areas:

Ordinarily, audio-visual equipment is purchased without thinking about power supply. For off-grid situations, power supply must be considered at the purchasing and planning stages. You should answer the following questions before buying:

1.1 How many needs will the system supply? Are there only one or many appliances?

Usually, those using audio-visual appliances will require lights in the same place they are based. They may want 2 or more additional appliances where they are based. A household might want lights, radio cassette player and a TV. Or an office might want a computer, a two-way radio and lights. It makes sense to design the energy system to meet the energy demand for all of these appliances at the same time, including future additions, if possible.

 1.2 How many hours are the appliances going to be used each day?

This is critical for the design of the energy system, and factors into the daily energy requirement calculation. You will have to provide this information to the system designer. See daily energy requirement calculation page for further information.

 1.3 What is the power rating and efficiency of each appliance?

When you have to pay for a power system (especially PV or wind), it makes sense to choose equipment that uses as little energy as possible. Most people who buy appliances for on-grid use do not stop to think about the efficiency of their equipment. When moving to, or setting up operations in an off-grid location, this becomes paramount. Table 1 shows typical power use ratings of a number of appliances.

1.4 Are the proposed appliances compatible with each other and with the energy system?

When selecting appliances, you need to make sure that either (1) they are of the same voltage, or (2) the system caters for all of the appliance voltages. For example, a 240VAC video would require an inverter if powered by a 12VDC solar electric system; and that cost should be included in system budgeting. In many cases, it would be easier to purchase a 12VDC colour video/TV set, which are now widely available.

2.0 Equipment Options

 Table 1: Typical Audio-Visual Appliances and their Power Requirements

Appliance

Typical power rating

(watts)

Typical use per day (hrs)

Voltage rating

Is PV a good choice?

(Typical system size)

Black and white TV

12-18 W

2-6 hrs

12VDC, or 110/240 VAC

Yes. 20 – 60 Wp

Colour TV

40-60 W

2-6 hrs

240/110AC or 12VDC

Yes. 80-150 Wp

Video

20 – 40 W

1-4 hrs

240/110AC or 12VDC

Yes. Add 20 Wp for ordinary use.

Radio-cassette (depending upon speaker output required as with PA system)

5 – 80 W

2 – 12 hrs

6-12VDC

Yes. 5-60 Wp

Public Address/PA System

(Amplifier, mixer and speakers)

50 – 100 W

1 – 6 hrs

12VDC or 110/240 VAC

Yes. 40 Wp or more, depending on size and usage

Desktop computer and monitor

400 W

4 - 8 hours

 110/240 VAC

Expensive (300 Wp or more). Use hybrid system.

Laptop computer

20-40 W

4-8 hours

Yes. 40 Wp

Two-way radio

5-10W standby, 40-50W transmitting

0.5-3 hours transmitting, 12 hours standby

Yes, normally 80 – 100 Wp

Fax/answering machine

30-60W

continuous

110/240 VAC

Could be (new technology with "sleeper" systems now coming on the market)

Slide projector

150 – 300 W

2 4 hrs/week

Overhead projector

150 – 300 W

2 4 hrs/week

2.1 Educational and Office Equipment:

2.1.1 Computers/Modems/Printers and Peripherals:

There are two general types of computers: desktop PCs with monitors and laptops with incorporated monitors.

NB: Laptops are always preferable in off-grid situations due to their lower energy use.

 2.1.2 Projectors/Overheads:

Slide projectors are available in both 110/220VAC and 12VDC. Compare the rated wattage of various units before selecting. They use comparatively large amounts of power to run bright, hot bulbs and cooling fans. Normally, slide projectors are used on an occasional basis (i.e., not every day), so their energy use is relatively small.

Overhead projectors are not commonly available in 12VDC. Their power consumption is about the same as slide projectors, but in many places they are used on a daily basis. Consumption from daily use of projectors will add significant costs to energy systems.

 2.2 Communication Equipment

Communication devices are common requirements in rural project offices or missions, and are in increasing use in rural, off-grid households and commercial establishments. They can be inexpensively powered by solar electric power or wind generator systems. You should carefully estimate the amount of time you will use your communication device to enable proper sizing of the energy system. Care should be taken to make sure that shadows from antennae do not shade solar modules, as this can greatly reduce output.

2.2.1 Two-way radios are the most common communication tool used in missions, police posts and in refugee operations. HF (high frequency) and VHF (very high frequency) radios are both used. Note that radio power consumption is much higher when transmitting than it is when receiving or on stand-by. You will need to calculate carefully how much time is spent transmitting. Under typical use, most HF radio systems can be powered by 80-100Wp of PV. NB: Suppliers of radios and remote telephone systems should be able to help design power systems for their products.

2.2.2 Telephones

2.3 Entertainment and Sound Equipment

2.3.1 Televisions and videos are increasingly in demand in rural areas by households, institutions and commercial groups.

2.3.2 Radio-cassettes, radios, stereos are the most common sources of entertainment for rural people. They also play a vital role in information access for rural people.

2.3.3 Public address (PA) systems are required at public service meetings, seminars and workshops, and at religious services, discos, concerts, wedding parties, sports events and political campaigns alike. PA systems are rated at 80 watts and greater, depending on the size of the venue. The rated size of the amplifier will provide an indicator of the system size required. Daily usage in hours must be factored into the sizing; obviously a system used daily in a mosque will require more power than one used occasionally and on weekends. There are a wide variety of public address systems available, and you can find them in 12VDC or 110/240VAC. Check with your supplier for estimated power usage.

Click on any of the icons below, or click here for further reading on audio-visual, or here for supplier information on audio-visual. If you wish to return to the Introduction, click below, or click on one of the other modules below. Click here for links to visit some good links to other Internet sites.

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