Improved energy efficiency in a major Brazilian public hospital

2 de agosto de 2006

The IEI’s Latin American Regional Initiative office (REI-LA) is taking part in a two-year project aiming to retrofit the 27 year-old lighting and air-conditioning systems of a public hospital located at the State University of Campinas (UNICAMP) as well as evaluate its results.

The project is funded by a local utility through the funds of its 1% charge for energy efficiency and R&D. UNICAMP has signed a performance contract with the utility.

The first part of the project was finalized in December 2005, reducing the energy consumption on the second floor of the hospital from 2.09 GWh to 1.14 GWh per year.

The main explanation for the huge reduction in energy consumption lies in the innovation made on fluorescent lamps since the hospital was constructed in 1978. Modern fluorescent lamps are generally 20% more energy efficient than traditional ones; the luminous efficacy (lumens/Watt) has increased, reactor losses have reduced, newer luminaries are equipped with alumina reflectors which better focus the illumination where needed, and the power factor has increased.

The table below presents the main results achieved.

 
Old system
New system Reduction

Installed capacity (kW)

345

135

210

Number of luminaries

2505

2505

 

Number of fluorescent lights

7824

3975

3849

Number of reactors

3933

2505

1428

Energy consumption (MWh/year)

2077

1142

934

Energy saving (%)

 

 

45%

Tariff (R$/MWh)

175

175

 

Annual economic saving (US$)

 

 

74 760

Corridor with the new lighting system. The illumination is 20 % higher than for the old system and the energy consumption is reduced by 45 %
 1 USD = 2.18750 BRL

Increased power quality

In Brazil, the critical lower value of the power factor is considered to be 0.92. By introducing the new illumination system at the hospital, the average power factor increased from 0.6 to 0.97. This improvement reduces losses in the hospital’s internal electrical system and it also decreases losses in the local distribution grid.

In addition, the amount of harmonic distortion was reduced from an average of 26% to 17% THD (Total Harmonic Distortion). Low THD reduces losses internally and externally (the same effect as a high power factor). And a low THD also reduces the stress on electrical equipments, increasing their life expectancy.
 

Increased end-user satisfaction

Despite reducing the energy consumption at the hospital by 45%, the illumination in lux (lumens/square meter) increased by 20 – 35%. This is reflected in the end-user satisfaction collected through questionnaires. With the old system, 45% of the users were satisfied with the illumination, while 84% are satisfied with the new system. 30% were unsatisfied with the old system, and only 3% answered that they were unsatisfied with the current illumination.

Calculating energy efficiency and project economy

In the project budget, it was estimated that the installed capacity would be reduced from 295 kW to 195 kW, and that the yearly consumption would be reduced from 1936 MWh to 1282 MWh. During the project, it was discovered that both the installed capacity and the energy consumption were underestimated for the old system. The real capacity was 345 kW and the annual energy consumption was 2077 MWh. Instead of reducing the installed capacity to 195 kW as budgeted, the new system ended up with an installed capacity of 135 kW.

Calculations after implementing the new system showed that the energy consumption was reduced to 811 MWh annually. This is a 61 % reduction compared with the old system. The corresponding reduction in energy cost is R$ 221,427 when an energy price of R$ 175/MWh is adopted.

In addition to calculations, physical measurements were undertaken. The measurements showed that the energy consumption was 1142 MWh after upgrading the electricity system, corresponding to an energy reduction of 45%, and annual savings of R$ 163.533,00.

The total project investment was R$ 380,000 (US$ 175,145). The forecasted pay-back period was 39 months, but as the energy consumption was reduced more than expected, the pay-back period will probably be much less. By applying the measured 45% reduction in energy consumption, an energy price of R$ 175/MWh, and an annual interest rate of 18%, the pay-back period more than halved (18 months).

Next step

IEI Latin America and ELEKTRO are currently involved in the second upgrading stage at the hospital. The objective is to replace the illumination system in the remaining five floors of the hospital and to upgrade the cooling system which at present is unable to deliver the cooling demand of the hospital. The second stage is slightly larger than the first stage.

Fluorescent lights and global warming – study made by the International Energy Agency

Corridor with the old lighting systemThe simple use of current technology could have a dramatic impact on global warming, if only we would adopt it. The low-energy light bulb and other efficient lighting systems could prevent a cumulative total of 16 billion tons of carbon from being added to the world's atmosphere over the next 25 years, according to a report by the International Energy Agency. The agency pointed out that it would not need any technology that is not already widely available and – far from costing money – it would save more than US$ 2,480 billion.

Artificial light accounts for almost one-fifth of the world's electricity consumption, substantially more than the output of all the nuclear power stations in the world. It generates around 1.9 billion tons worth of carbon a year, equivalent to nearly three quarters of the carbon coming from the exhaust of all the cars and light vehicles in the world.

That is only the start of the problem. Within 25 years, the global demand for artificial light is projected to be almost twice today's level as the developing world moves towards Western living standards. The average American family uses 10 times more artificial light than a Chinese home and more than 30 times as much as an Indian home. And there are 1.6 billion people in the world with no access to electricity at all.

The IEA says the amount of carbon coming from standard light bulbs could rise to three billion tons a year. "Without rapid action, the amount of energy used for lighting will be 80 per cent higher in 2030 than today," Claude Mandil, the executive director of the IEA, said. "However, if we simply make better use of today's efficient lighting technologies and techniques, global lighting energy demand need be no greater at that time."

Efficient lighting is such an obviously good idea economically that it is hard to explain why common sense and market forces have not

Corridor with the old lighting system

combined to bring it about. But efficient lighting can cost more in the short term. The best systems have installation costs and the people who install lighting systems are not the same as the users who will pay the bills.