Design-Build your existing Condo / Apartment withACE Services / ECP
Energy usage reduction projects for high rise residential buildings and commercial buildings
Those of us involved in the building management industry are constantly bombarded by sales personnel on energy savings gadgets, systems or ideas. No doubt all the systems do reduce energy consumption. However, not all gadgets, systems or ideas are feasible or justifiable to implement. Some gadgets or systems are too new and have not been perfected. The use of them often results in problems or failures. Some are too idealistic and the real practical results may be quite disappointing. Others, while resulting in savings, also introduce new spin-off problems.
Over the years, we have studied all new ideas that come onto the market. Many we have studied and rejected outright. Some we have modified and then used. Some we have used. And some, we have created from my own diligence and experience. Because we do not implement any design idea unless and until we have done due diligence and am satisfied, the ones we have implemented, have always been successful.
ACE would like to share the following successful energy/operating cost savings ideas with you. We have used them in my buildings and they have proven to work and to save operating costs. The savings are very high and payback periods are relatively short. As well there are rebates available from Enbridge/Union Gas and appropriate Hydro utility companies. Rebates are equal to the savings in the first year of operation after retrofit. In effect, the rebate offsets some of the capital cost and then after the short payback period the savings reduce the operating costs.
Boilers Old heating and DHW boilers are in the 50-80% efficiency range. New condensing boilers are 96%+ efficient. The increase in efficiency = lots of savings in gas consumption. Where DHW (Domestic Hot Water) is produced by a heat exchanger using heating water, the efficiency to produce the DHW is even lower. Heat exchangers are in the 50-60% efficient range. The compounded efficiency to produce the DHW could be as low as about 40%. Payback periods are higher for heating boilers (because they are only seasonally used) and much lower for DHW boilers because they are needed daily and on much higher demand volume than heating water. Rebates from Embridge or Union Gas often equate to about 25-30% of the retrofit cost. Boilers over 15 years old are prime candidates for retrofit. Past 15 years, they have finished their practical lives and are prone to failure. At that age, major costs to repair risk being wasted when the inevitable end of life of the boilers arrives. Often, unexpected leaks, major failures or death, mean scramble to replace them in the middle of winter. (Boilers fail when they are operating in the winter, not when they are idling in the summer.) Retrofitting them with newer energy efficient boilers reduces the maintenance cost and reduces operating costs.
A secondary advantage of replacing old boilers with new high tech high efficiency types is that the new boilers are very compact and pleasantly pointed. They free up lots of space in traditionally crowded boiler rooms. As an obvious indication of energy efficiency, the traditional boiler rooms are hot and comfortable rooms. In boiler rooms with high efficiency boilers, the boiler rooms are not hot. In fact, I have had a situation, where a window in a penthouse boiler room (which was always open in the past to dissipate heat from the hot room) had to be closed to prevent freezing of condensate drain pipes !!
In the case of DHW boilers, heat exchangers have much shorter lives than the boilers. On the average, heat exchangers have 1/3 to 1/2 the lives of boilers. When heat exchangers have to be replaced, replacing the heat exchanger DHW production with an independent high efficiency boiler system will be a better and excellent move.
There are many advantages for doing this :
a)If the heating boilers are also producing DHW, the boilers are larger. It means in the summer, with no heating required, these larger boilers have to continue to operate to produce DHW. With heating and DHW boilers being different and separate, only the smaller DHW boilers need to operate year round. The heating boilers will shut down in the summer.
b)As noted above, direct production of DHW instead of using a heat exchanger, saves one layer of inefficiency and so is more efficient. Multiple DHW boilers, each between 50-60% of peak DHW capacity, will result in a staged DHW production. Controllers can alternate each modular boiler to be the lead boiler, thus allowing even wear on the boilers. Modular boilers not only save on energy, but provide flexibility for maintenance and even eventual replacement. Instead of storing the DHW in a single large glass-lined storage tank, multiple smaller storage tanks will also provide flexibility for maintenance and replacement. The total capacity of the storage tanks will be calculated so that, together with the production capability of the modular boilers, peak demands will be met, without storage a larger than needed amount of DHW and then losing heat to the atmosphere.
c)With the DHW production separate, the heating boilers too could be modular and controlled to alternate on demand and with an outdoor temperature sensor to assist in demand anticipation.
Make up air units using gas heating (This section does not apply to buildings using heat pumps to cool and heat make-up air, or buildings using energy recovery systems.)
Make-up air units, unsuspectingly, is a major energy consumer in sealed high rise buildings. ASHRAE 62.1 requires the introduction of fresh air into the building. As soon as the outdoor air temperature drops below room temperature, the heaters in the make-up air units will activate to preheat the cold outdoor fresh air. The heaters, in fact, stay on continuously, during the heating season. Any savings in energy consumption equates to lots of savings in operating cost.
Conventional indirect gas fired make-up air units are 60-70% efficient. New condensing units are 99% efficient. Like boilers, the savings are tremendous. Rebates, like in the case of boilers, are about 25-30% of retrofit cost. Again, like boilers, existing units that are older than 15 years are prime candidates for retrofit. The average useful lives of make-up air units is about 15 years. Past 15 years, the maintenance cost becomes increasing higher with age and the units are prone to unexpected failures. In most buildings, the replacement can be at the same locations as the existing units and the distribution risers are reused. The cost of replacement is relatively low. But savings in 30-40% in efficiency represents a very substantial amount of operating cost.
Older buildings tend to have over designed make up air volumes. In the process of retrofit, systems should be reviewed and the revised to meet new ASHRAE 62.1. This too will result in energy savings. The only work caused by floor air volume changes, is simply re-setting of dampers.
Retrofitting with new high efficiency make-up air units requires little to no extra effort. The difference in equipment cost (higher efficiency units cost more) is practically offset by the rebates. Therefore not to, does not make practical sense.
Parking garage lighting
In the past, savings are realized with use of energy efficient fixtures. Now, the savings are realized with lighting controls. The cost to replace lower energy efficient fixtures with higher energy efficient types is high and the savings may only be 10-15%. The payback tends to be extremely long. That was the old way. The new say is to introduce controls so that light fixtures in unoccupied areas of the garage are switched off and switched on again only when occupancy is sensed. HID fixtures are not suitable for this application because of the time they need to warm up when switched on. Fluorescent fixtures work well for this application.
The savings is in switching the light fixtures off when not needed. This is no different than switching lights off in a room when the room is empty. The average savings is about 75%. The cost of the controls is relatively low. And so the payback period is relatively short. As well, the efficiency of the light fixtures is a minor factor in the savings strategy. Therefore, even if older existing light fixtures continued to be used with the controls, the savings is still very high and relevant. Of course, from an environmental perspective, older, lower efficiency light fixtures should be replaced. But to do so, will be for environmental reasons, and not as a viable operating cost savings.
To implement the light controls system, a garage is zoned into practical smaller zones and each zone’s lighting is controlled by an occupancy (motion) sensor. Lighting connected to the building emergency power are left continuously on, as required by Code. Properly designed, savings are about 75% or better. If this sounds too good to be true, consider this.
Parking lighting is normally on continuously. During the day, half the time, the garage is empty. In the night, better than 80% of the time the garage is empty. Average that, and the 75% savings is in fact very conservative. In cases where existing light fixtures are reused, payback period of 6-9 months are possible. Then there are rebates by the Hydro utility company. The rebates offset a large portion of the retrofit costs. In fact, rebates are for this purpose, to encourage initiatives to reduce energy usage.
Proper engineering is needed to make the controls system work and be functional. I have seen some garages having electricians implement this plan. The lack of proper engineering resulted in inconveniences and complaints. In one case, it actually resulted in high cost and low savings!! The replacement by LED fixtures, too, is not practical for garages and the cost is higher resulting in very long payback period. LED “fluorescent” lamps are very costly and so are LED flood light lamps.
Corridor and common area lighting
Corridor lighting is the same potential in energy savings as parking garages. The same design criteria is used as in garages i.e. some continuously lit light fixtures preferably on emergency power and other light fixtures zoned and lit upon detection of motion (occupancy). There is a potential implementation challenge for corridor lighting controls…. wiring. The implementation involves modifications to light fixtures wiring and the installation of wiring to occupancy sensors. Corridors normally have concrete slab ceiling that is plastered/sprayed. There are various possible solutions to the challenges and varies from building to building. Investigation is required to determine solution. An alternative plan is to replace the lamps in corridor lighting to LED types.
Windows
Solar gain through clear glass windows account for as much as 90% of the cooling load of a building, on a sunny day in summer. The rates of solar gain in Toronto is 100 btuh/sf for east facing windows, 164 btuh/sf for south and west facing windows. 120 sf of south or west facing windows will have a possible solar gain of about 20,000 btuh (almost 2 tons). A typical internal cooling load will be about 2000 btuh. Solar reflective films will reflect away the solar gain. Various reflectivity capabilities are available with 50% being the most practical and popular.
In this example, the film will reduce about 10,000 btuh or about 1 ton of cooling. 200 south and west facing suites with solar reflective film could reduce the cooling load of about 400 tons of cooling. The energy saved (central system and local unit compressors) will be about 250 kw per hour or possibly in excess of ½ million KWH a year!!! This energy savings initiative is most beneficial to buildings with central Hydro metering. In buildings where the building main cooling system is undersized, the use of solar film to reduce cooling load will also help ease the under sizing problem. Payback is about 2-3 years.
An added advantage of solar reflective films is that they also reduce visual transparency and therefore increase privacy. Concern about indoor plant health with reduction in ultraviolet rays is unfounded. Unless a 100% reflective solar film is installed, the amount of ultraviolet rays still able to penetrate is more than what indoor plant needs. A proof of this is that indoor plants do well in commercial office buildings. In most commercial office buildings, the reflectivity of the solar film is 75% or higher.
LED light bulbs
This is a simple non-engineering initiative and applicable to buildings without individual suite Hydro metering. If in-suite light bulbs are replaced with LED type, the energy savings can be 90% if incandescent lamps are replaced and 50% if compact fluorescent lamps are replaced. If the building purchases LED light bulbs and give them to the suites at no-charge, the savings will result in a payback on the light bulb investment, of about 1-2 years depending on the ratio of compact fluorescent to incandescent light bulbs involved. This is a simple initiative requiring no engineering. Because of the large volume purchase, special prices will be available from most suppliers.
CASE STUDY
Energy usage reduction projects specific to this building (18 Thorncliffe Park Dr., Toronto)
The use of electric baseboard heaters for heating in this building is very troubling. It is a massive energy operating cost. Associated with the electric heating is controls. Unless each heater is separately thermostatically controlled, a secondary problem causes high electricity usage. The thermostat can only sense the room/surrounding where it is located. At times, while the thermostat maintains this room/surrounding at the pre-set temperature, other rooms do not need heating and become overheated. Windows are opened to cool those rooms. At other times, other rooms may be cool and so to force the heaters to activate, the thermostat is set very high, resulting in overheating of the room where the thermostat is located.
This building should be converted to gas heating. It means the installation of a small gas furnace in each suite. Cooling becomes an easy option with the furnaces. The average cost to implement this is about $8,000-10,000 per suite depending on size and layout. The payback is 6-8 years. The payback period is higher than the other proposed items. However, it is still a good payback period and this plan does also introduce much appreciated comfort to the suites/residents.
How we work
▪The process starts with an initial feasibility and cost review. Part of this review is to investigate what upgrades or other repairs of related systems the client’s project facility needs. The thinking is that, as part of the retrofit, the project facility should be repaired or upgraded so that with the retrofit, the facility will operate trouble free and safely till the next retrofit.
▪A budget can then be produced for the client’s project funding planning purposes. This is presented in part of the project investigation report.
▪Then, once approved to proceed and the agreement is executed, the process of retrofit begins with engineering design and concluding with commissioning.
▪We continue to monitor the operation and follow up with system tweaking as required , we have real time technology that monitors every circuit in your complex at attractive prices
▪A separate proposal will be presented for an on-going maintenance contract. Good maintenance by a quality contractor is part of ensuring that operation savings are at the maximum , our ECP maintenance division has a complete program
Financing Program - Lease / Rental / 5 -10-15 yr programs
A.C.E. personnel will work closely with your financial needs and customize your project to fit your budget.
