ABSTRACT

The objective of Springer-Carrier’s Corporation in Brazil was to transform their existing facility in Canoas, PortoAllegre into a prototype “Factory of the Future”. Carrier’s goals were to increase productivity and reduce energy costs while minimizing initial investment costs transforming the factory into a world class facility, showcasing the best technologies and approaches for creating a superior work environment. These objectives were to be achieved by:

• implementing superior natural daylighting solutions;
• improving indoor air quality;
• providing solar driven air conditioning; and
• increasing the reliability of electrical power required to efficiently operate the facility.

By implementing this strategy, it is to be demonstrated that:

• the impact of rapidly rising utility costs can be contained;
• the factory owner would be in a positive cash flow situation; and
• by addressing energy and productivity, production costs would be greatly reduced.
  

1. INTRODUCTION

Springer-Carrier is undertaking the renovation in three phases, with the intent of increasing their employee’s
productivity as well as obtaining significant energy savings. Daylighting and solar powered cooling systems are the two most significant strategies to be implemented in achieving these goals. Up to date, the first of the three phases has been completed, and consisted of replacing 125,000 square feet of existing roof with a new saw-tooth roof structure that incorporates daylighting, while still allowing for a future incorporation of a solar array system in Phase II that will power an absorption cooling system for the entire factory. The objectives of the first phase were to:

• remove the existing roof and skylight system and implement a controlled daylighting system;
• integrate a new roofing system with improved insulation and radiant barriers;
• implement an absorption cooling system (that will be matched to the proposed Phase II solar systems
  requirements); and
• improve lighting conditions within the factory by adding task lighting and painting the interior with light colors.

The second phase will consist of designing, implementing, and maintaining a solar system that will occupy up to 87,000 square feet of roof area. The proposed system, to be constructed in increments, will be mounted on six sections (north facing) of the new Phase I sawtooth roof. The intended system will utilize Duke Solar’s VAC 2000 modules with non-imaging type collectors. The solar tubes will operate at a normal 200º C (392º F) and a pressure of 14.6 bars (212 p.s.i.) The system consists of evacuated tubes that will be assembled in pre-manifolded sections which fit into integrated mounting brackets implemented in Phase I. Once Phase II is completed the solar systems will:

• provide the thermal energy necessary to fuel 700 tons of double-effect absorption cooling and
• provide up to 200 kiloWatts of electrical power.
  

The third phase will potentially consist of adding 152,940 square feet of Duke Solar’s Power Roof system capable of providing 1.2 megawatts of power. The power roof is a unique, high temperature solar system that is a solar
collector as well as a weather-tight, well insulated roofing assembly providing excellent daylighting to the space
below. The proposed system will consist of 564 modules that are each 12 feet x 16 feet for a total of 108,288 square feet.

2. EXISTING CONDITIONS

Currently, throughout South America as well as the rest of the developing world, the majority of industrial factories are energy-inefficient, highly polluting, and generally provide poor working conditions for their employees. To the factory owner this results in lower productivity and higher utility bills. To the employee the results often translate into poorer attitude and greater health problems. To the community in which the factory is located, it means greater levels of air pollution. It is Springer-Carrier’s objective to demonstrate that these problems can be solved through the use of daylighting and solar driven absorption cooling.

The plant is powered by electricity, which is provided by the American Energy System (AES), and by a low-grade LP gas. The cost of the lower grade LP gas was $.46/therm. The facility requires approximately 1.14 million kWh per month. During the on-peak time of 6 pm to 9 pm the factory consumes 122,000 kWh and during off-peak it consumes approximately 1,015,000 kWh. The on-peak energy cost is $.23/kWh and the off-peak rate is $.03/kWh.

The cost of the low-grade LP gas is $113/1000 cubic meters or equivalent to $.43/gallon or $.51/therm. However, the Btu content is lower and estimated at 85,000 Btu/gallon versus typical LP gas at 91,000 to 92,000 Btu/gallon.
Currently only 6,000 cubic meters of LP gas are used per month (72,000 cubic meters per year).

Energy use Profile: The factory, in 1998, had a peak consumption in August of 3.4 megaWatts. The average monthly peak is 2.3 megaWatts and the lowest peak consumption was in May with 1.2 megaWatts.

Energy Inflation: Currently on peak electricity is $.23/kWh and off-peak electricity is $.03/kWh. If energy costs continue to rise at the same rate they have in Brazil since 1995, by the year 2005 the price of peak power will be $0.53/kWh and offpeak electricity will have risen to $0.07/kWh. Even if this current energy inflation rate of 15% per year can be reduced to 10%, energy costs in the year 2010 will have risen to $0.65/kWh for on-peak and $0.08 for off-peak electricity.

3. PHASE I'S DAYLIGHTING STRATEGY

The goal of Phase’s I daylighting strategy was to design a controlled daylighting system capable of lighting at least
one-half of the daylight hours of the day. To ensure success daylight sensors were employed, and additionally the floor surfaces, walls, columns and beams were painted to obtain an overall interior building reflectance of 50%.

The daylighting strategy designated produced 50 footcandles (500 Lux) at least half of the time from 7:00am
to 5:00pm and 30 Footcandles (300 Lux) at least half of the time. In addition, task lighting over specific equipment or assembly operations was implemented in areas that are frequently used at night. If daylighting was not implemented and even greater amounts of additional lighting (increasing light levels to 40 footcandles) were installed to bring the entire facility up to a reasonable standard, the cost to light and air conditioning would also increase. The Power DOE simulation results for this scenario indicated that the additional estimated cost per year would be $55,467. This yearly cost did not include the first cost of the extra cooling equipment required or of the extra light fixtures needed. It was projected that just the lighting cost to upgrade the factory by 10 footcandles (100 Lux) would require an additional 600 fixtures and be approximately $48,000. The daylighting strategy consisted of implementing south facing, vertical glazing into a new sawtooth roofing system. The south- facing vertical glazing minimized direct beam radiation from entering the space, and it created a uniform non-glare natural lighting condition. We specified a 6’-3” high, double-glazed Lexan with a high transmission (85%). The clerestory windows run the entire length of the building, and 7% of the total aperture area is mullions. In order to control the direct beam radiation that comes through the glass very early in the morning and late in the afternoon during the summer months, it was recommended that baffles be mounted perpendicular to the clerestory windows. Because this glare was limited to only a few hours during a couple months of the year, our suggestion was to evaluate the specific situations once the glazing was installed, and then implement the baffles where needed. In the great majority of the factory this was not problematic and the baffles were not necessary. The worst month would be in January when direct beam radiation would enter into the factory from 6:00am to 8:00am and 4:00pm to 6:00pm.

The daylighting strategy was designed to produce 50 footcandles, at least half the time from 7:00 am to 5:00pm,
and 30 Footcandles at least ¾ of the daylit hours. Using the Solarsoft-Daylite analysis programs we analyzed the
daylight behavior for a typical section of the factory trying different glazing amounts. Once the optimum glazing amount was established, we were able to produce daylighting schedules, which indicate the amount of
supplemental electric light required during the year to reach the desire lighting levels. These extensive schedule were in turn, input into Power DOE to produce a dynamic analysis of how the building performs over the course of the year. The immediately following chart summarizes the daylighting contribution between 7:00am and 5:00pm, with
30 footcandles, 40 footcandles, and 50 footcandles.

In order to evaluate the daylighting conditions at different times of the day, Radiance was used to simulate a sectional model of the factory by which glazing amounts and wall reflectances were tested.

Finally, in order to enhance the daylighting strategy, it was recommended that certain elements be repainted as an
integral part of the renovation in Phase I. Structural beams, walls and columns should be painted white (semi-gloss
white paint 70% reflectance). Wherever practical the floor should be painted light green (53% reflectance) to medium blue (49% reflectance).

4. PHASE I'S INSTALLATION OF AIR CONDITIONING

Well recognized is the relationship between productivity and the temperature and humidity of the workplace. Most
factories in Brazil are not air conditioned, despite indoor air temperatures often exceeding 37º C (98º F). Productivity certainly suffers in such working conditions. Brazilian law also mandates a maximum temperature for workers. Many factories are in violation of this requirement and the motivation for enforcement is now increasing. This initiative is intended to demonstrate how these issues can be dealt with cost-effectively. The second component of phase I was to install the absorption cooling equipment that in phase II will be powered by solar energy. The objective was to implement air conditioning throughout key occupied areas within the factory, install air filtration and fresh air make up systems, and install absorption cooling equipment that would eventually be powered by solar energy. The initial analysis conducted by Carrier indicated that the factory would require a 1000-ton unit of cooling.

The typical cost per ton for an industrial air conditioning system was approximately $1,800/ton. The total cost for a
1000 ton air cooled chiller would have been $1,800,000. However, with the daylighting, radiant barriers, painting recommendations, and lighting recommendations the estimated peak load dropped by a consistent 250 tons. This
equated to a first cost reduction in cooling equipment of $450,000.

5. PROJECTED COSTS AND SAVINGS

As manufacturing processes improve, energy costs are becoming a greater percentage of the overall product cost.
Because of the uncertainty of future energy costs, energy efficiency is becoming an increase priority. Since 1995
electricity prices in Sao Paulo have risen 73%. In the month of July and August of 1998 the average cost of electricity in Brazil had gone up over 11% while in Sao Paulo prices have increased a staggering 21%. To compete in the coming years, the “Factory of the Future” will need to be energy efficient.

Daylighting Savings: By implementing the daylighting strategy it was estimated that $450,000 would be saved by reducing the cooling equipment by 250 tons, and $48,000 would be saved by reducing the amount of electrical lighting that would have tobe upgraded. In this way the total initial capital cost savings amounted to $498,000 in the first year.

Productivity advantages: Currently 600 workers work in the factory areas to be renovated. By air conditioning the factory and introducing daylighting it is most likely that important productivity gains will occur. If these productivity gains are even a fraction of those experienced in other documented cases, the savings to management will be significant and the health of the workers improved. If productivity gains were approximately 1/3 of those experienced at daylit schools in North Carolina, and ¼ to a 1/5 of those obtained in California’s daylit schools, the increase in performance would be 5%. If the impact of introducing better quality air is only 1/3 that of what the US Environmental Protection Agency projects that could be achieved by reducing indoor air quality issues, another 1% in productivity could be realized. Currently the labor costs associated with the employees working in the factory are $1,983,529 per year. A 6% improvement in efficiency would result in first year savings for Springer-Carrier of $119,000 over. If general inflation continues to increase at 10% per year and worker salaries keep pace with inflation, the value of these productivity gains in 2005 will have risen to $191,649 and by 2010 it will have reached $308,650 annually.

Total Savings: The total cost for implementing daylighting and absorption cooling for the facility was $1,200,000. To this total costs we need to subtract $450,000 in order to account for a 250 ton reduction in equipment due to the enacted recommendations. Also $48,000 need to be subtracted from the total cost due to savings towards upgrading the electric lighting. After accounting for the total initial capital cost savings ($498,000) the total cost for implementing daylighting and absorption cooling is $702,000.