the answer is wood!.
my bro was complaining about a high electricity bill and was asking how to reduce it. so i thought i'd share the answer i gave him.
lighting
how much of lighting would you be using? light sources emit light as well as other electromagnetic radiation, like heat and microwaves. the amount if light emitted is represented by luminous efficacy (its efficacy and not efficiency and its not a spelling mistake), measured by lumens per W (lm/W).
listed bellow are efficacy values of various lamps. it is important to appreciate that the standard 3ft fluorescent lamp (tube light) has a high efficacy. combined with electronic ballasts this would be the best energy saver. but we can't buy electronic ballasts in the retail market. they are sold by agents usually to escos and contractors in bulk . if you already have standard fluorescent lamps, then don't expect a major change in your lighting cost.
| lamp type | efficacy range (lm/W) |
|---|---|
| standard filament lamp | 10-18 |
| standard 2ft fluorescent lamp | 51 |
| standard 3ft fluorescent lamp | 57 |
| standard 4ft fluorescent lamp | 42 |
| good quality compact fluorescent lamp (cfl) above 15W | 50-60 |
cooking
apart from lighting how can my brother save on his electricity bill? his wife cooks and they use the microwave a lot. lets evaluate that.
$i=0;
$data[$i]['method'] = 'microwave';
$data[$i]['secenergy'] = 'electricity';
$data[$i]['sec_energy'] = 3.6;
$data[$i]['eff'] = 75;
$data[$i]['cpu'] = 26;
$data[$i]['cpu_unit'] = 'kWh';
$data[$i]['cost'] = $data[$i]['cpu']/ ($data[$i]['sec_energy'] * ($data[$i]['eff']/100));
$i++;
$data[$i]['method'] = 'resistance heater (electric kettle, electric oven, etc.)';
$data[$i]['secenergy'] = 'electricity';
$data[$i]['sec_energy'] = 3.6;
$data[$i]['eff'] = 50;
$data[$i]['cpu'] = 26;
$data[$i]['cpu_unit'] = 'kWh';
$data[$i]['cost'] = $data[$i]['cpu']/ ($data[$i]['sec_energy'] * ($data[$i]['eff']/100));
$i++;
$data[$i]['method'] = 'gas cooker';
$data[$i]['secenergy'] = 'lpg';
$data[$i]['sec_energy'] = 45;
$data[$i]['eff'] = 45;
$data[$i]['cpu'] = 130;
$data[$i]['cpu_unit'] = 'kg';
$data[$i]['cost'] = $data[$i]['cpu']/ ($data[$i]['sec_energy'] * ($data[$i]['eff']/100));
$i++;
$data[$i]['method'] = 'clay fire wood stove';
$data[$i]['secenergy'] = 'fire wood (gliricidia)';
$data[$i]['sec_energy'] = 14;
$data[$i]['eff'] = 17;
$data[$i]['cpu'] = 10; // (rs / kg) / (14 MJ/ kg)
$data[$i]['cpu_unit'] = 'kg';
$data[$i]['cost'] = $data[$i]['cpu']/ ($data[$i]['sec_energy'] * ($data[$i]['eff']/100));
$i++;
$data[$i]['method'] = 'traditional three stone wood stove';
$data[$i]['secenergy'] = 'fire wood (gliricidia)';
$data[$i]['sec_energy'] = 14;
$data[$i]['eff'] = 8;
$data[$i]['cpu'] = 10; // (rs / kg) / (14 MJ/ kg)
$data[$i]['cpu_unit'] = 'kg';
$data[$i]['cost'] = $data[$i]['cpu']/ ($data[$i]['sec_energy'] * ($data[$i]['eff']/100));
?>
| cooking method | secondary energy | energy consumption (MJ/unit) |
efficiency of cooker (%) |
cost per unit (Rs/unit) |
utility (Rs/MJ) |
|---|---|---|---|---|---|
| per |
so cooking using fire wood is the cheapest but the smoke and ash removal is a put off. the bio energy association supplies gliricidia so if you're interested you can ask them. call 0112690546 for more info.
if you're boiling water using an electric heater - think again! its times cheaper to use wood and times cheaper to use your gas cooker to boil water!
useful data
energy star requirements for compact fluorescent lamps (cfls) ››› click here to view data
source: energy star
$i=0; $type='Bare Lamp';
$data[$type][$i]['task'] = 'Lamp Power < 15';
$data[$type][$i]['lux'] = 45;
$i++;
$data[$type][$i]['task'] = 'Lamp Power: ≥ 15';
$data[$type][$i]['lux'] = 60;
$i=0; $type='Covered Lamp - No Reflector';
$data[$type][$i]['task'] = 'Lamp Power: < 15';
$data[$type][$i]['lux'] = 40;
$i++;
$data[$type][$i]['task'] = 'Lamp Power: 15-18';
$data[$type][$i]['lux'] = 48;
$i++;
$data[$type][$i]['task'] = 'Lamp Power: 19-24';
$data[$type][$i]['lux'] = 50;
$i++;
$data[$type][$i]['task'] = 'Lamp Power: ≥ 25';
$data[$type][$i]['lux'] = 55;
$i=0; $type='Covered Lamp - With Reflector';
$data[$type][$i]['task'] = 'Lamp Power < 20';
$data[$type][$i]['lux'] = 33;
$i++;
$data[$type][$i]['task'] = 'Lamp Power: ≥ 20';
$data[$type][$i]['lux'] = 40;
?>
| Lamp Power (Watts) & Configuration | Minimum Efficacy: lm/W |
|---|---|
incandescent-lamp lighting data ››› click here to view data
source:
marks' standard handbook for mechanical engineers
10th edition
$i=0;
$bulbData[$i]['power'] = 25;
$bulbData[$i]['bulb'] = 'A-19';
$bulbData[$i]['lumen'] = 230;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 2500;
$i++;
$bulbData[$i]['power'] = 40;
$bulbData[$i]['bulb'] = 'A-19';
$bulbData[$i]['lumen'] = 474;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 1500;
$i++;
$bulbData[$i]['power'] = 60;
$bulbData[$i]['bulb'] = 'A-19';
$bulbData[$i]['lumen'] = 1060;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 1000;
$i++;
$bulbData[$i]['power'] = 75;
$bulbData[$i]['bulb'] = 'A-19';
$bulbData[$i]['lumen'] = 1190;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 750;
$i++;
$bulbData[$i]['power'] = 100;
$bulbData[$i]['bulb'] = 'A-19';
$bulbData[$i]['lumen'] = 1740;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 750;
$i++;
$bulbData[$i]['power'] = 150;
$bulbData[$i]['bulb'] = 'A-21';
$bulbData[$i]['lumen'] = 2873;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 750;
$i++;
$bulbData[$i]['power'] = 200;
$bulbData[$i]['bulb'] = 'A-23';
$bulbData[$i]['lumen'] = 4000;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 750;
$i++;
$bulbData[$i]['power'] = 300;
$bulbData[$i]['bulb'] = 'PS-30';
$bulbData[$i]['lumen'] = 6130;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 750;
$i++;
$bulbData[$i]['power'] = 500;
$bulbData[$i]['bulb'] = 'PS-35';
$bulbData[$i]['lumen'] = 10674;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 1000;
$i++;
$bulbData[$i]['power'] = 750;
$bulbData[$i]['bulb'] = 'PS-52';
$bulbData[$i]['lumen'] = 16935;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 1000;
$i++;
$bulbData[$i]['power'] = 1000;
$bulbData[$i]['bulb'] = 'PS-52';
$bulbData[$i]['lumen'] = 23510;
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['lumen']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 1000;
?>
| power consumption (watts, W) |
bulb size | luminous flux (lumens, lm) |
luminous efficacy (lm/W) |
rated life (hours, h) |
|---|---|---|---|---|
illuminance guide for selected tasks ››› click here to view data
source:
marks' standard handbook for mechanical engineers
10th edition
$i=0; $type='Commercial Drafting';
$data[$type][$i]['task'] = 'Conventional *';
$data[$type][$i]['lux'] = 1600;
$i=0; $type='Libraries';
$data[$type][$i]['task'] = 'Reading good print, typed originals';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Reading small print, handwriting, photocopies';
$data[$type][$i]['lux'] = 800;
$i++;
$data[$type][$i]['task'] = 'Active stacks (vertical, illumination)';
$data[$type][$i]['lux'] = 320;
$i=0; $type='Offices';
$data[$type][$i]['task'] = 'Conference rooms - conferring';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Conference rooms - typical visual tasks';
$data[$type][$i]['lux'] = 800;
$i++;
$data[$type][$i]['task'] = 'Conference rooms - typical visual tasks';
$data[$type][$i]['lux'] = 1080;
$i++;
$data[$type][$i]['task'] = 'Corridors, stairs, elevators';
$data[$type][$i]['lux'] = 220;
$i++;
$data[$type][$i]['task'] = 'General tasks, varying difficulty';
$data[$type][$i]['lux'] = 1080;
$i++;
$data[$type][$i]['task'] = 'Lobbies, reception areas';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Private';
$data[$type][$i]['lux'] = 880;
$i++;
$data[$type][$i]['task'] = 'Rest rooms, Toilets';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Video display areas';
$data[$type][$i]['lux'] = 800;
$i=0; $type='School';
$data[$type][$i]['task'] = 'Classrooms, laboratories';
$data[$type][$i]['lux'] = 800;
$i++;
$data[$type][$i]['task'] = 'Shops, Workshops';
$data[$type][$i]['lux'] = 1080;
$i++;
$data[$type][$i]['task'] = 'Sight-saving rooms, hearing-impaired classes';
$data[$type][$i]['lux'] = 1600;
$i=0; $type='Store';
$data[$type][$i]['task'] = 'Mass merchandizing, high activity';
$data[$type][$i]['lux'] = 1080;
$i++;
$data[$type][$i]['task'] = 'Self-service';
$data[$type][$i]['lux'] = 2200;
$i++;
$data[$type][$i]['task'] = 'Circulation, low activity';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Feature displays, low activity *';
$data[$type][$i]['lux'] = 1600;
$i++;
$data[$type][$i]['task'] = 'Feature displays, medium activity *';
$data[$type][$i]['lux'] = 3200;
$i++;
$data[$type][$i]['task'] = 'Feature displays, high activity *';
$data[$type][$i]['lux'] = 5400;
$i=0; $type='Industrial';
$data[$type][$i]['task'] = 'Garages, repair';
$data[$type][$i]['lux'] = 800;
$i++;
$data[$type][$i]['task'] = 'Garages, active traffic areas';
$data[$type][$i]['lux'] = 160;
$i++;
$data[$type][$i]['task'] = 'Loading platform';
$data[$type][$i]['lux'] = 220;
$i++;
$data[$type][$i]['task'] = 'Machine shops, Rough bench-machine work, simple assembly *';
$data[$type][$i]['lux'] = 540;
$i++;
$data[$type][$i]['task'] = 'Machine shops, Medium bench-machine work, moderately difficult assembly *';
$data[$type][$i]['lux'] = 1080;
$i++;
$data[$type][$i]['task'] = 'Machine shops, Difficult bench-machine work, assembly *';
$data[$type][$i]['lux'] = 1600;
$i++;
$data[$type][$i]['task'] = 'Receiving and shipping';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Warehouse storage rooms, Active large items';
$data[$type][$i]['lux'] = 160;
$i++;
$data[$type][$i]['task'] = 'Warehouse storage rooms, Active small items, labels';
$data[$type][$i]['lux'] = 320;
$i++;
$data[$type][$i]['task'] = 'Warehouse storage rooms, Inactive';
$data[$type][$i]['lux'] = 54;
$i=0; $type='Outdoor areas';
$data[$type][$i]['task'] = 'Storage yards, Active';
$data[$type][$i]['lux'] = 220;
$i++;
$data[$type][$i]['task'] = 'Storage yards, Inactive';
$data[$type][$i]['lux'] = 11;
$i=0; $type='Parking areas';
$data[$type][$i]['task'] = 'Open, high activity';
$data[$type][$i]['lux'] = 22;
$i++;
$data[$type][$i]['task'] = 'Open, medium activity';
$data[$type][$i]['lux'] = 11;
$i++;
$data[$type][$i]['task'] = 'Covered parking, pedestrian areas';
$data[$type][$i]['lux'] = 54;
$i++;
$data[$type][$i]['task'] = 'Covered night entrance';
$data[$type][$i]['lux'] = 54;
$i++;
$data[$type][$i]['task'] = 'Covered day entrance';
$data[$type][$i]['lux'] = 54;
?>
| Task | Illuminance (lux, lm/m2) |
|---|---|
fluorescent-lamp lighting data ››› click here to view data
source:
marks' standard handbook for mechanical engineers
10th edition
$i=0;
$bulbData[$i]['type'] = 'F15T12';
$bulbData[$i]['length'] = 1.5;
$bulbData[$i]['lamp'] = 15;
$bulbData[$i]['ballast'] = 4.5;
$bulbData[$i]['flux'] = 830;
$bulbData[$i]['power'] = $bulbData[$i]['lamp'] + $bulbData[$i]['ballast'];
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['flux']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 9000;
$i++;
$bulbData[$i]['type'] = 'F20T12';
$bulbData[$i]['length'] = 2;
$bulbData[$i]['lamp'] = 20.5;
$bulbData[$i]['ballast'] = 5;
$bulbData[$i]['flux'] = 1283;
$bulbData[$i]['power'] = $bulbData[$i]['lamp'] + $bulbData[$i]['ballast'];
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['flux']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 9000;
$i++;
$bulbData[$i]['type'] = 'F30T8';
$bulbData[$i]['length'] = 3;
$bulbData[$i]['lamp'] = 30.5;
$bulbData[$i]['ballast'] = 10.5;
$bulbData[$i]['flux'] = 2330;
$bulbData[$i]['power'] = $bulbData[$i]['lamp'] + $bulbData[$i]['ballast'];
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['flux']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 7500;
$i++;
$bulbData[$i]['type'] = 'F40T12';
$bulbData[$i]['length'] = 4;
$bulbData[$i]['lamp'] = 40;
$bulbData[$i]['ballast'] = 12;
$bulbData[$i]['flux'] = 2150;
$bulbData[$i]['power'] = $bulbData[$i]['lamp'] + $bulbData[$i]['ballast'];
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['flux']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 15000;
$i++;
$bulbData[$i]['type'] = 'F20T12';
$bulbData[$i]['length'] = 5;
$bulbData[$i]['lamp'] = 90;
$bulbData[$i]['ballast'] = 20;
$bulbData[$i]['flux'] = 6025;
$bulbData[$i]['power'] = $bulbData[$i]['lamp'] + $bulbData[$i]['ballast'];
$bulbData[$i]['efficacy'] = ceil ($bulbData[$i]['flux']/$bulbData[$i]['power']);
$bulbData[$i]['life'] = 9000;
?>
| Lamp | Length (feet) |
Lamp Power Consumption (watts, W) |
Ballast Power Consumption (watts,W) |
Total Power Consumption (watts,W) |
Luminous Flux (lumens, lm) |
Luminous Efficacy (lm/W) |
Rated Life (hours, h) |
|---|---|---|---|---|---|---|---|