Energy efficiency of vertical transportation
During the joint Conference held on 25th March 2015 the agreement on the scheme of the decree redefining the rules for the application of the methodology for calculating the energy performance, use of renewable sources in the buildings and the minimum requirements for energy performance was enshrined. The decree was approved on June 26, 2015 and published in the Official Journal on 15 July. With the new decree, the implementation of the Legislative Decree 63/2013 begins, converted into Law 90/2013, transposing the Nearly Energy Zero Building Directive (2010/31/EU), replacing the Legislative Decree 192/2005. Specifically, the Decree replaces the 59/2009 Presidential Decree, which has defined the methods of calculation and the minimum requirements for the energy performance of buildings and heating systems in compliance with article 4, paragraph 1 of the Legislative Decree. 192/2005.
The new provision updates the methodology for calculating the energy performance of buildings, taking into account the TS 11300-3 and TS 11300-4 technical standards about summer air conditioning, about the use of renewable energy and CTI Recommendation 14 on the calculation of primary energy.
LIFTS AND BUILDING CONSUMPTIONS
In addition to all the provisions relating to technological and design strategies to be implemented – the so-called “traditional” strategies which are already known and consolidated in some cases (i.e. thermal insulation, type of heating boilers, etc.) – this law has included lifts, escalators and moving walks among the systems to be improved or at least re-designed, built and installed, bearing in mind the need for reducing energy consumption.
We have to point out that the scope of the Law, at the moment, covers only the sector of service buildings.
But, given the special attention with which the European Union considers the energy saving issue and the huge difference between the number of residential and tertiary-type buildings, it is safe to predict that the same problems concerning the lift installations (escalators and moving walks are installed almost exclusively in the service or public sector), in a few years, will affect the energy consumptions of our domestic lifts.
It is not clear why, even today, in the case of a building renovation involving the lift, no account has to be taken of possible energy consumption reductions by using appropriate technical solutions.
The Italian Heat Technology Committee, the agency entrusted by the Ministry of Economic Development for the drawing of rules specifically related to the methods to be adopted to reduce consumptions and rules for the certification of the energy class of all buildings – published in 2015 the TS 11300-6 standard “Energy performance of buildings – Part 6: Evaluation of energy requirements for lifts, escalators and moving walks”.
This standard provides guidelines for certifiers in order to evaluate into the calculations of tertiary sector building energy performance, the energy consumptions of lifts, goods lifts, stair lifts, escalators and moving walks.
Maybe it’s time to abandon the rules and to focus on real aspects of vertical transportation energy consumption, both lift and escalator or moving walks.
“STAND BY” OR “RUNNING” SYSTEMS
The lift consumption is obviously connected to the use by people (generally called “traffic”) and that, at least approximately and ignoring any “imaginative” user behavior, is closely linked the building features and the number of users. We will be back to this when we deal with energy savings related to the system movement (the so called “running”). Maybe, it is not generally known by everyone that a stand-by lift consumes electricity and, in some unfortunate cases, in old systems which are rarely used for most of the day and night and are fitted with inefficient lighting and are always active, “stand by” energy consumption far more than what is required to move users their destinations.
This is a major problem to be solved by a designer in order to optimize the choices aimed at energy consumption reduction: what’s the “expected” use for the lift?
There are a few cases where the term “expected” can be replaced by the term “known”.
But this information is very valuable to make the appropriate choices from an energy point of view.
The less vague the information is, the easier is to achieve positive results from the savings point of view.
It is worth noting, however, that, even without taking into account the assessments related to energy saving, the exchange of information about the intended lift use between the installer and the construction manager at the time of sale is expressly required by law.
Some practical examples
It is quite intuitive that in the case of a system with very low traffic, more resources should be directed towards technologies aimed at reducing “stand by” consumptions, without neglecting energy consumption in “running” phases.
On the contrary, without neglecting the system consumption in standby, there is need to worry that much about “stand by” consumption when dealing with an installation with very heavy traffic (as it happens in a five-star hotel where day and night lift groups are continuously in operation), but of course it will favor the lowest “running” consumption compatibly with the high level of service expected. In this case, for example, the use of a motor control system with variable frequency is required in order to maintain low energy consumption during the several starts due to the intense traffic. On the other hand, speaking of numbers, it is not impossible that an old lift with fluorescent car lighting always on consumes more than 700 kWh per year (just for lighting). Switching off the lamps during the stop at landing, where this is permitted by law at the time of lift testing, just like it has been done for over 15 years for newly installed lifts, may therefore allow for considerable savings from the energy point of view, without the use of any sophisticated technology. It is clear that whatever the choice concerning the drive type or technology of the control panel, the use of automatic LEDs for the lighting system can only bring benefits but, as always, we must pay attention: not all LEDs allow a frequent sequence of switching on and off and, if not suitable for this type of operation, they may be short-lived. Therefore, how to choose among the various possible solutions “to save energy” in lifts? The important thing is to refer to a recognized calculation method and verify the various possible solutions with the same method.
Today, two standards may help us, one is the aforementioned TS 11300-6, the other is ISO 25745, made up of three parts of which the last two were published in April 2015.
The TS 11300-6 has the advantage of simplicity and is directed mainly to the evaluation at the design stage of the expected consumptions based on different technical choices, while the ISO 25745 is more refined and requires on-site measurements with appropriate tools and probably it is more suitable for the assessments to be made during major system modernization works. Whatever the choice, the most important thing is to refer to the same standard, avoiding the “translation” of the data obtained into different regulations, or without standard references with undefined “declarations”, believing that they are comparable.
We must not forget that in addition to the technological choice, maintenance also contributes to significant lift energy saving: wrong or neglected adjustments of the mechanical interface parameters, set at the time of installation, may vary over the time due to wear, leading to additional friction which is detrimental to the overall lift performance. This obviously affects the consumption of the lift motor.
Finally, we must emphasize the energy saving because it is very important and it should not be dealt with by “hearsay”. All the more in case of modernizations where the economic cost can be sizeable. We should avoid the “cheap” approach to the introduction or replacement of parts with components “consuming less” without a comprehensive and integrated project taking into account all the factors contributing to the total consumption. Moreover, it should be considered the use of components allowing a future expansion of the chances of the lift use based on the building requirements.
Coordinator of UNI G110 “Energy performance of lifts, escalators, moving walks and lifting systems for persons and goods”.
From Elevatori 1-2017
Questo articolo è disponibile anche in: Italiano (Italian)