Instructions About the Submission

OCCUPANCY SENSORS – THE PROMISE, THE DELIVERY, THE COST

K G Cram Electro Sense (Pty) Ltd, Kya Sands, Gauteng, South Africa

ABSTRACT systems. An analysis tool for projecting the environmental and social impacts will also be presented. Although use of occupancy sensors to control lighting is well established elsewhere, it is not in South Africa. 2. THE PROMISE - THE TECHNOLOGY The purpose of this paper is to present: a sensor technology overview (The Promise); a detailed case 2.1 HISTORY study documenting delivered results at a major South African commercial facility in consumption (kwh) Motion sensors using passive infrared (PIR) detection have saved, demand (kw) reduced and environmental and been around for many years. The commercialisation of this social impact (The Delivery); and cost and ROI technology dates to the 1970s and 1980s in the US. information for installation of sensors (The Cost). Installation information will include practical You see the modern day descendents of these devices every considerations such as the impact on staff and day in South Africa in the form of the so-called “security company operations. passives.” These primitive PIR sensors have evolved very little from the 1970s and 1980s and use a very basic form 1. INTRODUCTION of PIR detection of movement.

South Africa is experiencing an electricity crisis that was In recent years, passive infrared technology has evolved predicted as long as ten years ago [1]. Debating the causes dramatically and has been developed to far more or attempting to assign responsibility for this crisis is not sophisticated levels than the security passive. This has within the purview of this paper. The crisis is upon us and allowed the development of modern lighting control the time for action is now. Government and Eskom have systems that are practical for use in commercial and developed a plan for increasing electricity supply capacity industrial work environments, cost effective and [2] [3]. That plan will take years to implement and does not straightforward to install. impact or diminish the need to conserve energy as electricity generation, transmission and distribution all have Also in recent years, two new technologies for movement significant economic, social and environmental impacts. detection (and specifically human presence detection) have been developed. One of these is ultra sensitive One of the areas that will be examined in this paper is the microphonics technology coupled with sophisticated environmental and social impact of generating electricity learning circuitry and software that can effectively separate [4]. With historically low costs for electricity, end users out human generated noise from background noise. The have had relatively little reason to conserve and, therefore, other is motion detection by high frequency ultrasonic the general knowledge level of energy saving in South wave reflection. Africa is relatively low but is improving rapidly as individuals and companies struggle to cope with Each technology has its advantages and its limitations. increasingly frequent power outages. South Africa needs Some manufacturers have developed sensors that use the real, proven, cost effective and easily implementable three technologies in various combinations to achieve electricity savings solutions now. When someone else’s specific performance results. lights go off it is Eskom’s problem, when your lights go off it quickly becomes your problem. The state of the industry today is that there are PIR based sensors that are capable of detecting fine finger movement, This paper will examine the use of occupancy sensors to such as typing, at up to 3 – 4 metres with direct line of control commercial and industrial building lighting systems sight. There are microphonics based sensors that can by detecting human presence. Three areas will be “hear” human generated noise, even around corners, up to examined. First, The Promise. What is the technology and 6 metres or more depending upon the environment. There what exactly do occupancy sensors offer? Second, The are ultrasonic based sensors that can detect movement up to Delivery. A detailed case study of the documented results 8 metres and can do so through walls and other solid in terms of the electricity savings, the environmental objects. impact and the social impact of an occupancy sensor-based lighting control system as installed at one of South Africa’s Occupancy detection, as it is currently called, has come a newest and largest commercial office parks will be long way from the days of jumping up and down and presented. Third, The Cost. Detailed cost data for the case waving your arms to get the sensor to activate. study will be presented along with general cost analysis techniques for occupancy sensor-based lighting control 2.2 PASSIVE INFRARED TECHNOLOGY underground car parks and industrial areas such as open factory floors where there is direct line of sight for the PIR sensors work by detecting heat emitted by people or sensor. PIR sensors work best when the movement is objects. When the detected heat moves across two or more across switching zones rather than directly towards or away of the sensor’s switching zones, the sensor is activated. from the sensor. PIR sensors are relatively immune to false The more switching zones that a sensor has, the more triggering. sensitive the sensor is and the smaller the movement that it can detect. When the proper sensor is specified and installed in the correct location, modern PIR sensors provide a viable The original, and still widely used, security passives have option for lighting control in both the commercial and one infrared detector and 3 – 6 switching zones. The industrial environment. switching zones are the large flat areas on the lens of the sensor that break up the detection area of the infrared 2.3 MICROPHONICS TECHNOLOGY sensor. It takes large body movement to cross any two of the zones on a security passive. In addition, the infrared Microphonics sensors work by detecting sound rather than sensor itself is a basic, non-sophisticated sensor. heat. Highly sensitive, directional or omni-directional, microphones are used to pick up sounds then Automatic While inexpensive and reasonably suited to its intended Gain Control (AGC) circuitry and filters are used to purpose of detecting a body moving into a space, the separate out human generated noise from background noise security passive is totally unsuited to the task of lighting such as HVAC fans, computers, etc. control in a commercial or industrial environment due to its limited sensitivity and the propensity to turn off the lights Occupancy sensors incorporating advanced microphonics when someone is doing routine office work such as typing, technology are a more recent development [6]. These bookwork or computer work. sensors incorporate PIR as well as microphonics and are called dual technology sensors. They utilize PIR to “see” The most advanced PIR sensors on the market today utilise movement into the sensing area and microphonics to “hear” three much more sophisticated infrared sensors equally human generated noise once the PIR has activated the dispersed over 3600 and have over 1400 switching zones sensor. [5]. This results in the capability to detect fine finger movement such as typing at distances up to 3-4 metres and Sophisticated circuitry uses AGC to filter out background progressively larger movements up to 20 metres. "white" noise and to dynamically self-adapt a sensor to its environment so it detects only noises typical of human activity.

The PIR may be a full 3600 or it may be limited depending upon the application [7]. The PIR can detect hand movement up to 6+ metres and full body movement up to 16+ metres.

The microphonics can pick up sounds such as typing up to 6+ metres in typical environments. Detection range can be greater depending upon ceiling, wall and floor materials and in very quiet areas with little background noise.

Figure 1 – Typical PIR sensor installation

PIR sensors require direct line of sight so placement is critical to achieve proper control and eliminate user complaints that the lights go off unexpectedly. Range can be limited when sight lines are limited such as in open plan offices where there are high partitions between desks or pods of desks, or irregularly shaped areas that go around corners. Maximum range can be achieved in open plan Figure 2 – Typical microphonics sensor installation office areas with no partitions separating desks, One advantage of these sensors is that they only require direct line of sight to activate the PIR. The microphonics Modern HF sensors have reach and coverage similar to PIR can hear around corners or where there is obstructed line of and microphonics sensors [8]. HF sensors can pick up sight. hand motion up to 3+ metres and full body motion up to 8 metres. Dual technology microphonics sensors require direct line of sight for the PIR to activate the sensor so placement is Ultrasonic sensors are also incorporated into dual critical to achieve proper activation, such as when a person technology sensors with PIR [9]. These sensors use the enters a room, and eliminate user complaints that the lights longer range of a moderately sensitive PIR in conjunction do not come on when they enter the area. The with the small motion capability of the HF at closer range microphonics will then work even if there is not direct line to improve overall performance. of sight but range can be limited when sight lines are limited. Maximum range can be achieved in areas such as HF has another advantage/disadvantage which is the ability open plan office areas with no partitions separating desks, to read through solid walls. In non-uniform areas where large conference rooms, class rooms and open industrial there is not direct line of sight this can be an advantage. areas such as factory floors where there are reasonable Where the sensor reads through a wall to an adjacent background noise levels. The PIR part of the sensor works occupied area, or into a roof or ceiling area with birds or best when the movement is across switching zones rather rodents, it can false trigger the lights to go on in the than directly towards or away from the sensor while the unoccupied area. microphonics is omni-directional. PIR/microphonics dual technology sensors are highly immune to false triggering. Again, when the proper sensor is specified and installed in the correct location, PIR/HF dual technology sensors When the proper sensor is specified and installed in the provide a viable option for lighting control in both the correct location, PIR/microphonics dual technology sensors commercial and industrial environment. provide a viable option for lighting control in both the commercial and industrial environment. 2.5 THE PROMISE

2.4 ULTRASONIC TECHNOLOGY Regardless of the technology utilised, occupancy sensors share the common promise of most efficiently and Ultrasonic sensors, commonly called US for ultra sound or effectively controlling lighting usage. HF for high frequency, work by transmitting high frequency sound waves that strike any object in their path Occupancy sensor-based lighting control systems and reflect back to the sensor. Motion in the sensor’s range significantly outperform both complicated and costly disrupts the pattern of the reflected waves and activates the Building Management Systems (BMSs) and simple timers sensor. The sound waves are transmitted at inaudibly high [10]. frequencies. Of the three, only occupancy sensor-based systems are The biggest advantage of HF sensors is also their biggest fully legal under the Occupational Health and Safety Act, disadvantage. They are sensitive to any motion, not just 1993 [10]. Per the Act, it is illegal to have any workplace human generated motion and, therefore, have historically illuminated to less than the specified lux level in the Act been prone to false triggering. When used for lighting when there are workers present. control the result is that the lights may be on when there is no one there, thus reducing the savings. BMSs and timers only turn lights on and off based on time, not occupancy. When a worker stays late, comes in early, or unexpectedly needs to work in an area where the timer or BMS has not been pre-programmed to keep lights on, the lights can go out with significant safety concerns.

With an occupancy sensor-based system if there is human presence the lights will be on and if not, they will be off. Customer satisfaction with any system that automatically turns lights on and off is a significant factor. This is why virtually all BMS and timer systems eventually end up being over-ridden and any savings significantly reduced or negated altogether.

Finally, an occupancy sensor-based lighting control system guarantees the lowest electricity consumption by the lighting system and the lowest operating cost for the light Figure 3 – Typical ultrasonic sensor installation system because the lights are on when they need to be and work patterns in the various buildings. Every light fitting only when they need to be. in every area of all buildings and the underground car park was counted. An Electro Sense Proactive Energy In conclusion, all sensor technologies described here are Management SystemTM was then designed for the facility. capable of efficient and effective lighting control but will The system was designed to control the vast majority of only be as successful as the audit and design work that lights with the following exceptions: precedes installation. A knowledgeable, experienced and competent designer and installer of occupancy sensor-  Exterior building façade lighting was not based lighting control systems is critical to a successful end controlled for architectural reasons. That decision result and customer satisfaction. is currently under review in light of the massive savings that were achieved with the interior 3. THE DELIVERY lighting.

3.1 CASE STUDY – INTRODUCTION  Stairwells and the inside of lifts were not controlled for emergency safety reasons. Dimension Data built a new modern office park facility in Although the sensors turn the lights on instantly, Bryanston in the northern suburbs of Johannesburg to Electro Sense recommended and Dimension Data house its major operations as well as that of tenants. The agreed that these lights would not be controlled as facility is an office “campus” appropriately called The sensor light control was new in SA at the time and Campus. people needed to get used to the idea and operation. These lights represented a very small It consists of 17 interconnected buildings totalling just over percentage of the overall lighting. 80,000 m2 of office space beneath which is a contiguous underground car park totalling 113,000 m2. The buildings  Lift lobbies and stairwell lobbies were not form the shape of the letter D when viewed from above. controlled. Again, even though the sensors turn There is a cricket pitch/athletic field/outdoor concert venue the lights on instantly when someone enters an in the centre of the D and a 9 hole pitch and putt golf area, it was recommended by Electro Sense and course on the perimeter. Arguably it is one of the most agreed by Dimension Data that these lights would modern and efficient office facilities in South Africa. stay on so that when lift doors opened or someone exited a stairwell door, at least some lights would The basic facility (16 of 17 buildings and the underground be on and a person would not have to take even parking) was completed in 2003 with the final tenant the first step into an unlighted area. Sensors were building completed in late 2006. placed so that the first step into the lighted lobby area would turn on lights as far as 40 metres The lighting system installed at The Campus consists away, thus ensuring no one ever stepped out into mainly of highly efficient fluorescent fixtures with 2x40 darkness. Again, these lights represented a very watt PL40 lamps in each fixture. In addition, there are a small percentage of the overall lighting. variety of other lighting types such as 50 watt halogen downlights, a relatively small number of 36 watt The Campus is a typical South African office facility in fluorescents in 1, 2 and 3 lamp fixtures and finally, a small that the vast majority of lights burn 24/7/365. In most number of various sized compact fluorescent fixtures areas there are no light switches even if someone did want (CFLs). All fluorescent fixtures already had energy to turn the lights off. efficient electronic control gear before this case study was performed. A summary of the parameters of the test are as follows:

The Campus was the demonstration project for a lighting Total number of buildings 3 control system called the Electro Sense Proactive Energy Total watts of switchable lighting 154,644 Management SystemTM. Electro Sense (Pty) Ltd is a Total sensors required 461 Johannesburg based company that specialises in occupancy Average watts controlled per sensor 335 sensor-based lighting control systems [11]. Average cost per KW hour for 2004 R 0.152 Electro Sense approached Dimension Data in November Saving percentage projected 67% 2003 with an offer to reduce the operating costs for The Campus by reducing electricity costs for the lighting 3.2 CASE STUDY – RESULTS system. Reduced consumption of electricity by the lighting system was predicted to create a massive savings on the 3.2.1 Introduction lighting portion of the electricity bill. The project was conducted through the Eskom Demand An exhaustive audit of the lighting system at The Campus Side Management (DSM) program. One requirement of was completed in December 2003 along with an analysis of that program is for the results to be independently measured and verified (M&V). This independent testing is conducted by a number of university M&V teams around the country. Tshwane University is the lighting M&V team Table 2 – Electrical Demand kw, Weekdays for the Gauteng area. Day AM AM AM Midda PM PM PM Given that this was the first major installation of this Part Off- Std Peak y Std Peak Std Off- system in SA, it was decided to install and test 20% of the peak peak system at The Campus to verify the savings achievable Time 00:0 06:0 07:0 10:00 18:0 20:0 22:00 before continuing with full facility wide rollout. Two 0 – 0 – 0 – – 0 – 0 – – Dimension Data occupied buildings and one tenant 6:00 07:0 10:0 18:00 20:0 22:0 00:00 occupied building were chosen as representative of the 0 0 0 0 entire facility. Baselin 157 156 161 158 151 150 150 e The Tshwane University M&V team installed data logging With 11 82 139 144 86 40 24 meters on the lighting circuits of the test buildings and sensors conducted baseline measurements of both consumption Savings 146 74 22 14 65 110 126 (kwh) and demand (kw) to establish a baseline. The % 93% 47% 14% 9% 43% 73% 84% baseline was established in March 2005. Savings

The sensor control system was then installed and 3.2.4 Demand Results - Saturdays subsequent as-installed measurements were taken on the same lighting circuits using the same meters that had been Table 3 below shows the before and after demand in kw of used for the baseline. Data was taken over a two month the lights in the test buildings for the average of four period during July and August 2005. Data and results for consecutive Saturdays of measurement. These Saturdays the test were reported by Tshwane University for the month coincide with the weekdays above. of August 2005. Table 3 - Electrical Demand kw, Saturdays 3.2.2 Consumption Results Day AM AM Midda PM PM Table 1 below shows the before and after consumption in Part Off- Std y Off- Std Off- kwh of the lights in the test buildings. Baseline and with peak peak peak sensor data each represents the total of four weeks (28 Time 00:00 07:00 12:00 18:00 20:00 consecutive days) of measurement. – - - - - 07:00 12:00 18:00 20:00 00:00 Table 1 – Electrical Consumption kwh Baselin 156 155 155 155 155 e Baseline 600,995 kwh With 12 39 37 18 14 With sensors 87,333 kwh sensors Savings 513,662 kwh Savings 144 116 118 137 141 % Savings 85.5 % % 92% 75% 76% 88% 91% Savings 3.2.3 Demand Results - Weekdays 3.2.5 Demand Results - Sundays Demand was measured at 15 minute increments for both the baseline and with the sensors installed. This data was Table 4 below shows the before and after demand in kw of then summarised by standard Eskom day part and reported the lights in the test buildings for the average of four separately for weekdays, Saturday and Sunday per Eskom consecutive Sundays of measurement. These Sundays convention. coincide with the weekdays above.

Table 2 below shows the before and after demand in kw of Table 4 - Electrical Demand kw, Sundays the lights in the test buildings for the average of five weekdays (Monday – Friday) for four consecutive weeks Day Part Day Avg (28 consecutive days) of measurement. Time 00:00 - 24:00 Baseline 154 With 21 sensors Savings 133 % Savings 86% The projected kwh savings for The Campus after full 3.2.6 Peak Demand Reduction installation of the system is 614,633 kwh per month. Table 7 shows the environmental impact of these savings. The limiting item for Eskom in South Africa at the moment is the weekday evening peak demand. This is the time of day when Eskom has the least surplus generating capacity and when power shortages and load shedding are most likely to occur. A summary of the evening peak demand reduction results achieved is shown in Table 5 below.

Table 5 – Evening Peak Demand Reduction - %

Weekda 43% Table 7 Environmental Impact of the Dimension Data y Campus Electricity Savings Saturday 88% Sunday 86% Saved kwh per 513,662 kwh month 3.2.7 Environmental Savings Achieved and Social Water saved 652,351 litres Impact Coal not used 251,694 kg Ash not produced 68,122 kg 3.2.7.1 Environmental Savings Achieved Ash not emitted 149 kg S02 not emitted 3,883 kg

For every kwh of electricity produced there is an N0X not emitted 1,824 kg environmental impact. For every kwh of electricity saved C02 not emitted 457,159 kg there is both an environmental and a social impact. 3.2.7.2 Social Impact Eskom monitors its environmental impact and publishes data showing the resources used and the pollutants and by- There are many social impacts that can be quantified from products produced in generating electricity. In South saving electricity. Three that are easy to grasp are as Africa, over 90% of our electricity is produce from coal- follows. fired power plants. The first relates to the usage of electricity itself. One of Coal-fired power plants have a significant environmental South Africa and Eskom’s priorities in the past 12 years impact. From a resource standpoint, there is the coal and has been electrification, which is providing electricity to water consumed. From a pollutant and by-product the many low income people and families living in standpoint, there is the coal ash produced, the coal ash previously non-electrified areas, both rural and urban. emitted into the atmosphere, the sulphur dioxide and nitrous oxides emitted into the atmosphere and the C02 A 2001 report [12] documented that the average low emitted into the atmosphere. income family uses approximately 500 kwh of electricity per month. Therefore the social impact of the savings in Table 6 shows the resources used and the pollutants and kwh can be quantified in terms of the equivalent number of by-products produced for each kwh of electricity generated. low income families that the electricity saved from this project would support. Table 6 – Resources Used and Pollutants/By-products Produced per kwh Electricity Generated The second social impact relates to water usage. Potable water use varies significantly between different sectors of Resources No. kg Used/Resource per kwh society and different countries. The upper end of the water and or Produced/Pollutant per kwh use spectrum is first world users who consume 150 – 250 Pollutants litres per person per day. The lower end of the water use Resource spectrum are third world users who live more than 1 km Water used 1.27 litre per kwh from a potable water source and need to carry all water Coal used .49 kg per kwh back to their dwelling. These people use as little as 3 – 5 Pollutant litres per person per day. Ash produced .13262 kg per kwh Ash emitted .00029 kg per kwh A recommendation has been made [13] that an S02 emitted .00756 kg per kwh international standard of 50 litres of potable water per

N0X emitted .00355 kg per kwh person per day be adopted as meeting the basic needs for C02 emitted .89 kg per kwh drinking, bathing, cooking and sanitation. Therefore the social impact of the savings in kwh can be quantified in terms of the equivalent number of people that the water materials including sensors and associated wiring to saved from this project would support. install the sensors, all installation and commissioning labour and project management fees. The third societal impact relates to the production of the greenhouse gas carbon dioxide (C02) that results from the The fully-installed and commissioned cost per sensor can generation of electricity. Although there are many ways to vary from approximately R1200 per sensor to R3000 per look at the impact of C02 production, one way that most sensor depending upon the size of the facility, the people can easily relate to is the amount of C02 produced complexity and difficulty of installation, the number of by an average automobile driving an average number of individual light fittings to be controlled by each sensor, kilometres per month. Therefore the social impact of the the environment in which the sensor will be located and savings in kwh can be quantified in terms of the equivalent the type of sensors required. number of cars that would need to be removed from the roads to equal the saved C02 from this project. For example, industrial facilities can be much more challenging for installation due to high ceilings and Table 8 shows the social impact of the three factors industrial machinery. Car parks typically require extra described above. contactors and the use of conduit to surface mount wiring and the sensors themselves. Table 8 – Social Impact For most businesses an ROI of less than 36 months is Social impact per month No. considered a good standard for investment. Occupancy No. of low income families supported with 1027 sensor-based lighting control systems should typically electricity give an ROI of less than 36 months and can be less than No. of people supported with water for basic needs 429 18 months. Equivalent no. of cars removed from the roads 2167 5. CONCLUSION As can be seen, the social impact of saving electricity that is wasted when no one is there to need the lights on is The following conclusions can be drawn from this case significant. study. The occupancy sensor-based lighting control system as installed and tested at the Dimension Data Campus 3.2.8 Customer Acceptance and Satisfaction facility in Bryanston:

Customer acceptance of the system was extremely high 1. functions as promised; that is, it turns the lights on with few complaints received. Of those complaints and keeps them on whenever anyone is present received, most related to the placement of a sensor. On and turns the lights off and keeps them off when some occasions, office areas were remodelled or rearranged no one is present, with the result that a sensor wound up on the other side of a new office wall. In all cases, repositioning of a sensor or 2. delivers immediately measurable and verifiable adjusting the sensor’s field of view corrected the problem. savings,

Most staff members working at The Campus report that 3. is cost effective with an ROI of 36 months in a they like the sensors and feel good that they are there as it facility that has over 12 years left on its lease, makes them feel they and their company are doing something beneficial for the country and the environment. 4. has significant positive environmental and social benefits, 4. THE COST 5. will provide significant long-term savings as The cost of the system installed and commissioned at the electricity costs are only predicted to rise over the Dimension Data Campus and described in this paper was next 10 years. R5,449,350. Overall, occupancy sensor-based lighting control systems The return on investment (ROI) is 36 months. Given that are considered attractive to businesses from the multiple Dimension Data had over 12 years remaining on their perspectives of upfront cost, electricity savings, ROI, lease at the time of installation and that the system is positive social and environmental impact and good projected to save them over R22,000,000 over the next 10 corporate governance. years, it was an straightforward business decision for them.

On a per sensor basis the cost of this system was R2150 per sensor which included the upfront auditing of the lighting system at The Campus, system design, all http://www.queensu.ca/msp/pages/Project_Publicatio ns/Series/4.htm

[13] Gleick, P. H.: “Basic Water Requirements for Human Activities: Meeting Basic Needs, Water International, 21, 1996, pp 83-92

REFERENCES:

[1] Etzinger, A.: “Eskom: Power Struggles” SABCNews.com, Principal Author: http://www.sabcnews.com/features/eskom Principal author: Kenneth Cram [2] O’Connor, P.: “Eskom’s Generation Capacity holds a Bachelor of Science degree Expansion Plans” ESI Africa, Issue 1 2006, pp 40 – Please insert in Mechanical Engineering from 42 Passport Size Worcester Polytechnic Institute in Photograph Worcester, Massachusetts, USA. [3] Gcbashe, T.: “Chief executive’s report” Eskom Here At present he is a Director of Annual Report 2006”, Electro Sense (Pty) Ltd and is one http://www.eskom.co.za/annreport06/chiefexecutivesr of the developers of the Electro eport.htm Sense Proactive Energy Management SystemTM. [4] Green, E.: “Environmental Impact” Electro Sense, http://www.electrosense.co.za/enviro.php Presenter: The paper is presented by Kenneth Cram. [5] Steinel http://www.steinel.de/en/produkte_fuer_fachkunden/b ewegungsmelder_profiserie/ir_sensoren_fuer_wand_ decke_und_gang/is_3360

[6] sensorswitch http://www.sensorswitch.com/CompanyOverview.asp x

[7] sensorswitch http://www.sensorswitch.com/OnlineCatalog.aspx

[8] Steinel http://www.steinel.de/en/produkte_fuer_fachkunden/b ewegungsmelder_profiserie/hf_sensoren/hf_3360

[9] Hubbell http://www.hubbell- wiring.com/OccupancySensors.asp

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[11] http://www.electrosense.co.za/

[12] Fiil-Flynn Maj. And the Soweto Electricity Crisis Committee: “The Electricity Crisis in Soweto” Occasional Papers Series #4, 2001