Heaters and Air Conditioners

In many areas today the buses have air conditioners in the summer and compartment heating in the winter, which certainly ads to the comfort.

I often get questions about what the fuel consumption impact is of heaters and air conditioners.

As always it depends a lot on the user and under which conditions the bus is running.
If the air conditioner (AC) is used just a few months, mostly at noon, the impact is limited. However, in Hong Kong for example the power outtake increase in average by 30-50%  for the city double deckers on a yearly basis.

A couple of years ago I made a study on the fuel consumption of the heater on a bus-fleet in Sweden. The buses were using standard heaters from November to March, a period of five months. The heater was only used to give additional heat to the passenger compartments. i.e. engine heating in the morning was managed by an electrical ramp system.

Below I present some data that I have gathered from some different studies of larger fleets.

Yearly Average fuel consumption increase in a statistical analysis of large fleets:
AC Central Europe 6%
AC Israel 12%
Heater Finland 10%
Heater Sweden 6%

It essentially means that when the AC is running the fuel consumption is in average increased by about 20% for one bus.

The trick is to use the comfort equipment when required, but no more than that.

Electrifying!

When visiting Shanghai last week we got some hands-on experience of electric buses. Our Chinese joint venture, Sunwin, offers a series of different electric buses: super capacitor, battery and hybrid buses.

Electric buses, with less demand for infrastructure, already today offer advantages to trams and trolley buses for low speed city traffic.

Sunwin has delivered around 160 battery buses to Shanghai. Most of them use the battery exchange system, where the buses are equipped with batteries lasting for 2-6 hours’ operation, depending on duty cycle and utilisation of air conditioner. The battery exchange is one possible option for buses with long working hours and harsh duty cycles.

Figure: The Battery exchange station can swap batteries on eight buses simultaneously

Figure: Battery exchange is now a routine, with a constant flow of buses entering and leaving the station

Another option is to equip the buses with batteries for a full workday. More batteries are required and the load capacity of the bus will decrease a bit, but on the other hand the charging can be conducted during the night rest.

Figure: Bus “tanking” electricity 3-4 hours over night

Which solution is better?

Depending on the requirements, different solutions will be favourable. In the end it is a matter of balancing the passenger capacity versus the electric range. In general, very slow city traffic is favourable for today’s electric buses.  Typically less than 1 kWh/km is used for the slow city operation, without air conditioner. The daily range will be 150-250 km, depending on required capacity.

Figure:  Morning breaks in Century Park

When travelling, some exercise is welcome. But, what is Jörgen Sjöstedt doing at seven o’clock in the morning? As the morning breaks the people enter the Century Park for some exercise, Chinese gymnastics or just a walk.

Volvo Ocean Race Alicante

It’s sailing season again!

Seeing the crews taking good bye of their families is truly heart breaking. Today the Volvo Ocean Race started in Alicante. The six teams first made some laps along the coastline and then took off for Cape Town.

Yesterday, we showed our new product line and had some information activities with invitees. I presented the environmental features of the new product line. I’m really proud of our progress and no doubt Volvo Bus Corporation has done a fair deal of efforts to become the leader in environmental performance.

Today, I got the opportunity to join one of spectator-boats to see the start of the Volvo ocean race. We were very fortunate to have Roger Nilsson, the legend, as our guide.  Roger Nilsson has himself taken part in seven Whitbread/Volvo round the world races.  In addition he was also navigator when Orange II took the “round the world record” when making the roundabout in 50 days.

 

Roger Nilsson, legendary ocean race skipper

Roger Nilsson, legendary skipper for the first time he is not participating

The start was thrilling, Groupama took a 720⁰ penalty already the first lap. Team New Zealand with Camper had their show-off and is clearly a tight team. Their teamwork paid off on the short track of the start where the timing in the manoeuvers are important. Then Team Sanya got into technical problems and had to pass the leeward mark before turning. Puma was hot already before the start and went through a series of sails and simulated the start a couple of times. Telefonica were in their home waters and allowed themselves to keep some distance in order not to hazard their equipment. Team Abu Dhabi with Ian Walker as skipper won the in-port race last Saturday. And now the race is on, it will be most interesting to follow the race on the home page.

Alicante, Camper rounding up as first after the first lap

The rules have been modified a bit and the crews are not allowed to have as many sails on board as before. This was clearly seen already at the start where some had to choose a too big and others a too small sail for the first straight. This clearly brings a new dimension into the race.