Archive for the ‘Blog’ Category
Exoclimes.com is a website maintained and animated by professional astrophysicists at the University of Exeter and the University of Oxford. It is a website devoted to discussion around the study of planetary atmospheres outside the Solar System. The website has now reached it’s beta phase. If you haven’t already I would recommend you take a look.
A screenshot from the new website
The Dyson Hot is a commercial air heater that became available during autumn 2011. Dyson claims that it is a very efficient heater which excels beyond the more conventional heater by quickly and evenly heating a room. Being many times more expensive than most of the other heaters on the market it was of interest to scientifically quantify the claims by Dyson. The aim of this experiment has been to assess the performance of the Dyson Hot by comparing it to a standard heating oven. Although this has not done in a professional test lab, great care has been given to make sure the measurements were as accurate as possible.
The two heaters, the Dyson hot and the conventional heater, were placed at a distance of 3.04 meters (10 ft) away from a temperature module based on the DS18B20 (info). The temperature module was suspended in the air so that it was not affected by the material it would have otherwise been lying on. The power consumption was measured using a energy meter. The relative humidity in the room was controlled by a Duracraft Dehumidifier
| Heater | Power consumption |
| Conventional Heater | 2125 ± 12 W |
| Dyson Hot | 1951 ± 3 W |
The data was sampled at a frequency of once per minute. Prior to recording the data the room temperature was measured to be stable within 0.5 °C. The error of the temperature module is given to be ± 0.5 °C by the manufacturer. The measurements were both started at 15.0 ± 0.5 °C and stopped after 90 minutes.
Temperature curves between the conventional heater and the Dyson Hot, both rotating and non-rotating. The Dyson Hot, regardless of mode, is more efficient at heating a room.
The conventional heater started heating the room at 15.0 ± 0.5 °C with a relative humidity of 73 ± 5 % as measured by the TFA humidty meter
The Dyson Hot started heating the room at 14.75 ± 0.5 °C with a relative humidity of 73 ± 5 % as measured by the WH2080 Weather Station
The Dyson Hot started heating the room at 14.88 ± 0.5 °C with a relative humidity of 72 ± 5 % as measured by the WH2080 Weather Station
It is clear from the results that the Dyson Hot is indeed more efficient at heating a room. Not only was the room warmer after 90 minutes, but the Dyson Hot had also used less electricity. After 90 minutes the conventional heater had used 3.188 kWh whilst the Dyson Hot used in the same time 2.927 kWh, a difference of 0.262 kWh. Initial tests showed that a similar relative humidity was required for an accurate comparison. The Dyson Hot also seemed to push the hot air around more efficiently as shown in the figure below. We are not able to quantify just how much more efficient the Dyson Hot is at distributing heat as the heaters were placed at a fixed distance during all the measurements. Neither the Dyson Hot or the conventional heater gave off a burnt dust smell. The major downside of the Dyson Hot is the price. Assuming a conventional heater costs about £ 12 the Dyson Hot currently priced at £ 269.99 is then 22.5 times more expensive. One might thus argue that it is more convenient to use two or more conventional heaters to warm several rooms instead of having to move the Dyson Hot around from room to room.
A figure from the Dyson website showing the distribution of heat between a conventional heater and the Dyson Hot.
The Dyson Hot is without doubt more energy efficient and thus more cost effective. It is also better at heating a room, both in terms of speed and heat distribution. The major setback is the price. If you decide to get the Dyson Hot and you liked this scientific review please buy from the link below:
For a proper scientific review of the Dyson Hot go to this post.
Despite being only 58cm tall, this device still manages to warm my entire living room relatively quickly. It’s controls are very intuitive and the controller is easy to use. The Dyson Hot itself hardly heats up making it easy to just grab and move to another room should you need to.
Not major downsides at all. The price is quite steep and I was really worried I was paying to much for a heater. After seeing it’s results I am no longer of that opinion. At the highest air speed level it is not exactly quiet, but this can be counteracted by turning down the air speed.
I do not work for Dyson or anything like that. Normally I don’t write reviews either. However, since I now own a Dyson hot and I was at the time not able to find any reviews on it, I thought it best I wrote this one.
If you have questions about the Dyson Hot, feel free to use the comment section below.
The dwelling of the HARPS intrument
One of today’s highlights was seeing the room where the HARPS instrument is being kept. For it be able to achieve accurate radial velocity measurements the instrument has be kept at a constant temperature and pressure. I was fortunate to be shown the room where the instrument is kept locked inside a carefully monitored subroom. Due to us humans emitting heat, the visit had to be rather quick and we had to remember to close the door after us to make sure this nights observers did not loose any measurement accuracy.
Here the HARPS instrument lies locked inside. The HARPS room is kept at a very precise temperature and pressure. If it were to be opened it would take days for the temperature to return to the stable conditions required for measuring radial velocities at the 1 m/s level.
"First Light" - A little bit of history written on the whiteboard inside the old abandoned control room.
Astronomers are not able to obtain the transmission spectra of all the Hot Jupiters discovered thus far. With today’s instruments there are about 10 good targets that allow for transmission-based atmospheric detections (Sing et al. 2009b). These stars, which allow for transmission spectroscopy to be done, have the following attributes in common. Either they orbit a bright host star which in turn gives a better signal to noise (S/N), or they orbit a smaller star which leads to a deeper transit, providing a larger planet-to-star contrast. Also if the exoplanet has a large atmosphere (lower surface gravity, higher effective temperature) it is also easier to detect. Of all the Hot Jupiters discovered thus far, two planets stand out as being the easiest to measure, HD209458b and HD189733b. Almost everything known about Hot Jupiters to this date, comes from the study of these two planets.
The escaping atmosphere of HD 209458 b (Credit: Alfred Vidal-Madjar)
HD 209458 b has been the subject of intense study since the first planetary transits were detected (Charbonneau et al. 2000, Henry et al. 2000, Mazeh et al. 2000). It was the first planet to have it’s atmosphere detected using transmission spectroscopy (Charbonneau et al. 2002). What Charbonneau et al. (2002) detected was absorption from sodium which caused a 0.02% deeper light curve relative to simultaneous observations of the transit in adjacent bands. The presence of sodium was later confirmed by Snellen et al. (2008) who used a ground based telescope (Subaru Telescope). Despite this sodium detection, it was not as deep as predicted by a model which assumed a cloudless planetary atmosphere with a solar abundance of sodium. This lead to number of theories such as there being a low primordial abundance of sodium and/or clouds present in the upper atmosphere, to mention a few. Later Rowe et al. (2008) showed that HD 209458 b had a significantly lower albedo than Jupiter using the MOST (Microvariablity and Oscillations of Stars) satellite. This ruled out the presence of bright reflective clouds in the atmosphere. It is now thought that a low sodium abundance is due to condensation (where sodium condenses into sodium sulfide) or ionisation. This is supported by the observation of a sudden abundance change of sodium from the lower atmosphere (where the abundance is about 2 times the solar abundance) to the upper atmosphere (where it is about 0.2 times that of the solar abundance) (Sing et al. 2008). Recent discoveries include the the presence of water in the atmosphere (Beaulieu et al. 2010) and as well as atomic hydrogen, oxygen, and ionized carbon in the upper atmosphere (Koskinen et al. 2010).
Me with my astronomer face on.
Me pretending to do something useful in the NTT control room
The La Silla observatory is located in Chile and is ESO’s original observing site. It is located in the southern part of the Atacama desert at an altitude of 2400 meter.
A few of the telescopes at the La Silla observatory
La Silla sadly shows signs of economic cut backs with many smaller telescopes decommissioned. I was surprised at the sheer amounts of telescopes here.
The main hotel and restaurant
The site itself is very beautiful and has spectacular views.
View from La Silla observatory
The sun setting and giving way to the spectacular night sky
The astronomer himself enjoying the sunset
The ESO Guest House
The ESO guest house in Santiago is lovely colonial looking place.. It is a quiet haven perfect for astronomer who has had a long travel. It has nice grounds, a fountain, a swimming pool and a coffee machine. For more info on the guest house see ESO’s website.
General view of the La Silla observatory, as seen from the road that leads to the Las Campanas Observatory.
This week I will be travelling to Chile to observe with the New Technology Telescope (NTT). I plan to share my experiences here.
The Exoclimes 2012 conference will be held in Aspen, Colorado on January 16-20, 2012. Online registration for the Exoclimes 2012 conference is now available at the Aspen website, by following this link, and click on “Winter applications”. You will need to register and then select “Exoclimes 2012″.
From the exoclimes.org website:
Planetary atmospheres are complex and evolving entities, as mankind is rapidly coming to realise whilst attempting to understand, forecast and mitigate human-induced climate change. In the Solar System, our neighbours Venus and Mars provide striking examples of two endpoints of planetary evolution, runaway greenhouse and loss of atmosphere to space. The variety of extra-solar planets brings a wider angle to the issue: from scorching “hot jupiters” to ocean worlds, exoatmospheres explore many configurations unknown in the Solar System, such as iron clouds, silicate rains, extreme plate tectonics, and steam volcanoes.
Exoplanetary atmospheres have recently become accessible to observations. What observations are possible in the foreseeable future? And how will they constrain the climate on other worlds?
Observational exoplanet astronomer studying the atmospheres of exoplanets. Interested in public outreach and conveying my interest in astronomy to others.
