Bhatar Construction in Northern Pakistan

Pakistan was hit by a devastating earthquake in October 2005. Soon afterwords the government of Pakistan formed the Earthquake Reconstruction and Rehabilitation Authority, commonly known as ERRA. ERRA created 11 training centers for reconstruction of private homes destroyed in the earthquake. One of the techniques promoted in this reconstruction effort was the so called "Bhatar" method of construction.

Bhatar consists of reinforced stone masonry where parallel horizontal timber beams are inserted into the stone masonry at regular intervals to ensure coherence of structure. This is a much more economical option than typical construction which requires transport of cement, bricks and steal to remote mountainous regions. The houses constructed in this fashion are not only earthquake resilient but also energy efficient since the stone masonry acts as an insulator to heat and cold.

Bhatar Construction

Bhatar Construction

Bhatar House

Bhatar House

Earthquake Resistant and Energy Efficient Homes - PAKSBAB

After the devastating earthquake of 2005 which destroyed nearly half a million rural homes in Pakistan, there was an urgent need to build earthquake resistant homes. Thus came into being PAKSBAB which is the short form of Pakistan Straw Bale and Appropriate Buildings. So far PAKSBAB, from its limited resources, has build 27 homes in northern parts of Pakistan. These homes have been built using indigenous resources and by training the local people in construction of straw bale houses.

A typical straw bale house has an area of 576 square feet and costs $3000 on average. This  turns out to be $5.2/square feet which is less than half the cost of brick and mortar houses. A typical home comprises of two rooms, a verandah and a kitchen and requires around 1200 hours of labour. So 6 people working for 8 hours daily can construct a straw bale house in 25 days!

The main advantages of straw bale houses over brick and mortar houses are highlighted below.

1. Energy efficiency, since straw is a good insulator

2. Non toxic products are used (light straw, clay and wood)

3. Cheap materials are used resulting in a cost that is half that of a regular house

4. Resistant to earthquakes

Energy Efficient House

Tightly packed walls and a gravel weighted foundation creates better weather-proofing

 

Energy Efficient House

Twice as energy efficient as a conventional house, straw bale makes for environmentally friendly earthquake-proof homes

Energy Efficient House

Clay-plaster reinforced, a fabricated straw bale house costs half the expenses of modern building for every square foot

Straw bales required for the construction of these energy efficient and earthquake resilient homes are built using manually operated farm jacks and locally manufactured compression moulds. Furthermore the local industry is being encouraged to supply straw bales and other materials required for these projects. Additional appropriate building methods that PAKSBAB is promoting include passive solar, rainwater catchment, solar lamps, high-efficiency cooking and heating, and the use of natural building materials such as light straw clay, wattle and daub, and cob.

Can I Run My Air Conditioner on Solar

Air Conditioner on Solar

Air Conditioner on Solar

I have been asked this question many time by my friends "Can I Run My Air Conditioner on Solar". The short answer to this question is YES YOU CAN. For the longer version you would have to read rest of the article below.

Lets assume that you have a basic unit that is categorized as 1-ton. Now the way Air Conditioners work is that they draw a lot of current at the start, as much as three times the normal steady state current. So a 1-ton AC might be drawing only 1200 Watts at steady state, it may require as much as 3600 Watts at start up. Now there are two ways to solving this problem. Either you can put up 3600 Watts of Solar Panels on your roof and operate your system only when peak sunshine is available. Or, the better option is to have enough panels to run the AC at steady state and use some batteries to provide the initial peak current or power. These batteries will also provide back up after solar hours and when the electricity from the main grid is not available.

One company providing solar solutions in Pakistan recommends installing 1800 Watts of solar panels and 600 Ampere Hours of batteries. So assuming that we have 6 hours of peak sunshine available the solar panels would be able to run the AC for about 6 hours directly on solar energy (assuming an average power consumption of 1800 Watts). After the solar hours the battery would be charged by the main grid and can provide backup of at around 4 hours (12 V x 600 Ah / 1800 W =4 hours). Also one must not forget that to convert DC voltages to AC voltages you would need an inverter and for controlling the charge and discharge cycles of the batteries a charge controller would be needed. Usually the modern solar inverters have built in charge controllers which somewhat limits the costs.

After going through all this technical jargon the question that needs to be answered is "How Much Would This System Cost". The answer to this is around Rs.450,000 including transportation and installation. You might think that this is too high a cost, but think of it this way, even if you are saving Rs.5000 on your electricity bill per month you would have saved enough to offset the cost in about 8 years. And solar panels would last you much longer than 8 years (typically around 25 years).

Solar Car Build by Islamabad Entrepreneur

An entrepreneur in Islamabad has built a solar car that can run at 80 km/hour and has a range of 80 km. The car has solar panels on all its sides and roof which provide the energy to run the car. The car can also be plugged into an electrical socket to charge the batteries when they get discharged and solar energy is not available. According to the the designer all components have been locally manufactured except for the motor which has been imported from overseas (and obviously panels must have been imported as well). The current version of the car is a 2-seater but a 4-seater is also under construction.

Solar Car

Solar Car

Solar Car

Solar Car

The car is registered in Islamabad under the local laws. The company that invented this car, known as Economia, wants to commercialize this car by offering it has an alternate to taxis running on CNG and/or fuel. The company has submitted a proposal to the Government of Pakistan to allow it to start a local taxi system in Islamabad with 30-40 taxi stands in important areas of the city. This is a very encouraging development but it remains to be seen if it is able to taste commercial success.

According to the specs provided on the website the 2-seater version runs on a 2.2 KW motor whereas the 4-seater version runs on two 2.2 kW motors. The operating voltage of the motor and batteries is 48 V. The car is expected to be highly efficient and cost only Rs. 1/km. The price of the different versions range from Rs. 350,000 to Rs. 525,000.

Parameter ECO-1/ECO-1L ECO-2GL
Voltage of Battery 48 V 48 V
Seats 2-4 4
Power 2.2 kW x 1 2.2 kW x 2
Distance Per Charge 80 km 80 km
Charge Time 2-3 hours 2-3 hours
Maximum Speed 40-60 km/hr 60-80 km/hr
Motor 2.2 kW x 1, 48 V 2.2 kW x 2, 48 V
Charger 48 V, 20 A 48 V, 20-40 A
Controller 48 V, 90 A x 1 48 V, 70 A x 2

Note:

1. Input of 2.2 KW at 48 Volts means the motor needs 45 Amps to run.

2. If the solar panels on the car are about 500 W (100 W for each side and 100 W for the roof) the car would need to charge for about 4.4 hours in the sunlight to provide 1 hour of drive time. Realistically speaking, the 500 W panels would be producing only half the rated power since they cannot all be aligned to the sun at the same time.

3. Assuming that when the batteries are fully charged they can provide 2.2 KWhr of energy or simply 2.2 KW for one hour. At Rs. 15 per unit the cost for charging the batteries from an electrical outlet comes out to be Rs.33. Now if this car is able to drive for one hour at 60 Km/hour the cost per km would be Rs. 0.55 (this is assuming 100% efficiency which is practically not possible).