A 9-foot in diameter solar furnace, even under optimum conditions, will turn a cup full of water into steam in about one hour. A 1 hp steam engine, the smallest we make, requires 3 to 5 gallons of water turned to steam every hour. Worse, a medium-pressure steam engine (80 to 150 psi) requires incoming steam as hot as 366 degrees F. (185 C, 150 psi). The steam that leaves the exhaust port is still at 264 degrees F (128 C).

[[http://www.efunda.com/materials/water/steamtable_general.cfm Steam calculator]]

""
<table class="large" border="1">
<tbody>
<tr>
<td rowspan="2" bgcolor="#FFFFCC"><a href="http://www.engineeringtoolbox.com/pressure-d_587.html">Absolute<br />
pressure<br />
</a> <i>(kPa, kN/m²)</i></td>


<td rowspan="2" bgcolor="#FFFFCC"><a href="http://www.engineeringtoolbox.com/temperature-d_291.html">Temperature<br />
</a> <i>(^oC)</i></td>

<td rowspan="2" bgcolor="#FFFFCC"><a
href="http://www.engineeringtoolbox.com/density-specific-weight-gravity-d_290.html">Specific<br />
Volume<br />
</a> <i>(m³/kg)</i></td>


<td rowspan="2" bgcolor="#FFFFCC"><a
href="http://www.engineeringtoolbox.com/density-specific-weight-gravity-d_290.html">Density</a><br />
- <em>ρ -<br />
</em> <i>(kg/m³)</i></td>

<td colspan="3" bgcolor="#FFFFCC">Specific Enthalpy of</td>


<td rowspan="2" bgcolor="#FFFFCC">Specific<br />
Entropy<br />
of Steam<br />
- <em>s -<br />
</em> <i>(kJ/kgK)</i></td>

</tr>

<tr>
<td bgcolor="#FFFFCC">Liquid<br />
- <em>h_l -<br />
</em> <i>(kJ/kg)</i></td>


<td bgcolor="#FFFFCC">Evaporation<br />
- <em>h_e -<br />
</em> <i>(kJ/kg)</i></td>

<td bgcolor="#FFFFCC">Steam<br />

- <em>h_s -<br />
</em> <i>(kJ/kg)</i></td>
</tr>

<tr>
<td>0.8</td>


<td>3.8</td>

<td>160</td>

<td>0.00626</td>

<td>15.8</td>

<td>2493</td>

<td>2509</td>


<td>9.058</td>
</tr>

<tr>
<td>2.0</td>

<td>17.5</td>

<td>67.0</td>

<td>0.0149</td>


<td>73.5</td>

<td>2460</td>

<td>2534</td>

<td>8.725</td>
</tr>

<tr>
<td>5.0</td>


<td>32.9</td>

<td>28.2</td>

<td>0.0354</td>

<td>137.8</td>

<td>2424</td>

<td>2562</td>


<td>8.396</td>
</tr>

<tr>
<td>10.0</td>

<td>45.8</td>

<td>14.7</td>

<td>0.0682</td>


<td>191.8</td>

<td>2393</td>

<td>2585</td>

<td>8.151</td>
</tr>

<tr>
<td>20.0</td>


<td>60.1</td>

<td>7.65</td>

<td>0.131</td>

<td>251.5</td>

<td>2358</td>

<td>2610</td>


<td>7.909</td>
</tr>

<tr>
<td>28</td>

<td>67.5</td>

<td>5.58</td>

<td>0.179</td>


<td>282.7</td>

<td>2340</td>

<td>2623</td>

<td>7.793</td>
</tr>

<tr>
<td>35</td>


<td>72.7</td>

<td>4.53</td>

<td>0.221</td>

<td>304.3</td>

<td>2327</td>

<td>2632</td>


<td>7.717</td>
</tr>

<tr>
<td>45</td>

<td>78.7</td>

<td>3.58</td>

<td>0.279</td>


<td>329.6</td>

<td>2312</td>

<td>2642</td>

<td>7.631</td>
</tr>

<tr>
<td>55</td>


<td>83.7</td>

<td>2.96</td>

<td>0.338</td>

<td>350.6</td>

<td>2299</td>

<td>2650</td>


<td>7.562</td>
</tr>

<tr>
<td>65</td>

<td>88.0</td>

<td>2.53</td>

<td>0.395</td>


<td>368.6</td>

<td>2288</td>

<td>2657</td>

<td>7.506</td>
</tr>

<tr>
<td>75</td>


<td>91.8</td>

<td>2.22</td>

<td>0.450</td>

<td>384.5</td>

<td>2279</td>

<td>2663</td>


<td>7.457</td>
</tr>

<tr>
<td>85</td>

<td>95.2</td>

<td>1.97</td>

<td>0.507</td>


<td>398.6</td>

<td>2270</td>

<td>2668</td>

<td>7.415</td>
</tr>

<tr>
<td>95</td>


<td>98.2</td>

<td>1.78</td>

<td>0.563</td>

<td>411.5</td>

<td>2262</td>

<td>2673</td>


<td>7.377</td>
</tr>

<tr>
<td>100</td>

<td>99.6</td>

<td>1.69</td>

<td>0.590</td>


<td>417.5</td>

<td>2258</td>

<td>2675</td>

<td>7.360</td>
</tr>

<tr>
<td bgcolor="#FFCCCC"><strong>101.33</strong></td>


<td bgcolor="#FFCCCC">100</td>

<td bgcolor="#FFCCCC">1.67</td>

<td bgcolor="#FFCCCC">0.598</td>

<td bgcolor="#FFCCCC">419.1</td>

<td bgcolor="#FFCCCC">2257</td>

<td bgcolor="#FFCCCC">2676</td>


<td bgcolor="#FFCCCC">7.355</td>
</tr>

<tr>
<td>110</td>

<td>102.3</td>

<td>1.55</td>

<td>0.646</td>


<td>428.8</td>

<td>2251</td>

<td>2680</td>

<td>7.328</td>
</tr>

<tr>
<td>130</td>


<td>107.1</td>

<td>1.33</td>

<td>0.755</td>

<td>449.2</td>

<td>2238</td>

<td>2687</td>


<td>7.271</td>
</tr>

<tr>
<td>150</td>

<td>111.4</td>

<td>1.16</td>

<td>0.863</td>


<td>467.1</td>

<td>2226</td>

<td>2698</td>

<td>7.223</td>
</tr>

<tr>
<td>170</td>


<td>115.2</td>

<td>1.03</td>

<td>0.970</td>

<td>483.2</td>

<td>2216</td>

<td>2699</td>


<td>7.181</td>
</tr>

<tr>
<td>190</td>

<td>118.6</td>

<td>0.929</td>

<td>1.08</td>


<td>497.8</td>

<td>2206</td>

<td>2704</td>

<td>7.144</td>
</tr>

<tr>
<td>220</td>


<td>123.3</td>

<td>0.810</td>

<td>1.23</td>

<td>517.6</td>

<td>2193</td>

<td>2711</td>


<td>7.095</td>
</tr>

<tr>
<td>260</td>

<td>128.7</td>

<td>0.693</td>

<td>1.44</td>


<td>540.9</td>

<td>2177</td>

<td>2718</td>

<td>7.039</td>
</tr>

<tr>
<td>280</td>


<td>131.2</td>

<td>0.646</td>

<td>1.55</td>

<td>551.4</td>

<td>2170</td>

<td>2722</td>


<td>7.014</td>
</tr>

<tr>
<td>320</td>

<td>135.8</td>

<td>0.570</td>

<td>1.75</td>


<td>570.9</td>

<td>2157</td>

<td>2728</td>

<td>6.969</td>
</tr>

<tr>
<td>360</td>


<td>139.9</td>

<td>0.510</td>

<td>1.96</td>

<td>588.5</td>

<td>2144</td>

<td>2733</td>


<td>6.930</td>
</tr>

<tr>
<td>400</td>

<td>143.1</td>

<td>0.462</td>

<td>2.16</td>


<td>604.7</td>

<td>2133</td>

<td>2738</td>

<td>6.894</td>
</tr>

<tr>
<td>440</td>


<td>147.1</td>

<td>0.423</td>

<td>2.36</td>

<td>619.6</td>

<td>2122</td>

<td>2742</td>


<td>6.862</td>
</tr>

<tr>
<td>480</td>

<td>150.3</td>

<td>0.389</td>

<td>2.57</td>


<td>633.5</td>

<td>2112</td>

<td>2746</td>

<td>6.833</td>
</tr>

<tr>
<td>500</td>


<td>151.8</td>

<td>0.375</td>

<td>2.67</td>

<td>640.1</td>

<td>2107</td>

<td>2748</td>


<td>6.819</td>
</tr>

<tr>
<td>550</td>

<td>155.5</td>

<td>0.342</td>

<td>2.92</td>


<td>655.8</td>

<td>2096</td>

<td>2752</td>

<td>6.787</td>
</tr>

<tr>
<td>600</td>


<td>158.8</td>

<td>0.315</td>

<td>3.175</td>

<td>670.4</td>

<td>2085</td>

<td>2756</td>


<td>6.758</td>
</tr>

<tr>
<td>650</td>

<td>162.0</td>

<td>0.292</td>

<td>3.425</td>


<td>684.1</td>

<td>2075</td>

<td>2759</td>

<td>6.730</td>
</tr>

<tr>
<td>700</td>


<td>165.0</td>

<td>0.273</td>

<td>3.66</td>

<td>697.1</td>

<td>2065</td>

<td>2762</td>


<td>6.705</td>
</tr>

<tr>
<td>750</td>

<td>167.8</td>

<td>0.255</td>

<td>3.915</td>


<td>709.3</td>

<td>2056</td>

<td>2765</td>

<td>6.682</td>
</tr>

<tr>
<td>800</td>


<td>170.4</td>

<td>0.240</td>

<td>4.16</td>

<td>720.9</td>

<td>2047</td>

<td>2768</td>


<td>6.660</td>
</tr>

<tr>
<td>850</td>

<td>172.9</td>

<td>0.229</td>

<td>4.41</td>


<td>732.0</td>

<td>2038</td>

<td>2770</td>

<td>6.639</td>
</tr>

<tr>
<td>900</td>


<td>175.4</td>

<td>0.215</td>

<td>4.65</td>

<td>742.6</td>

<td>2030</td>

<td>2772</td>


<td>6.619</td>
</tr>

<tr>
<td>950</td>

<td>177.7</td>

<td>0.204</td>

<td>4.90</td>


<td>752.8</td>

<td>2021</td>

<td>2774</td>

<td>6.601</td>
</tr>

<tr>
<td>1000</td>


<td>179.9</td>

<td>0.194</td>

<td>5.15</td>

<td>762.6</td>

<td>2014</td>

<td>2776</td>


<td>6.583</td>
</tr>

<tr>
<td>1050</td>

<td>182.0</td>

<td>0.186</td>

<td>5.39</td>


<td>772</td>

<td>2006</td>

<td>2778</td>

<td>6.566</td>
</tr>

<tr>
<td>1150</td>


<td>186.0</td>

<td>0.170</td>

<td>5.89</td>

<td>790</td>

<td>1991</td>

<td>2781</td>


<td>6.534</td>
</tr>

<tr>
<td>1250</td>

<td>189.8</td>

<td>0.157</td>

<td>6.38</td>


<td>807</td>

<td>1977</td>

<td>2784</td>

<td>6.505</td>
</tr>

<tr>
<td>1300</td>


<td>191.6</td>

<td>0.151</td>

<td>6.62</td>

<td>815</td>

<td>1971</td>

<td>2785</td>


<td>6.491</td>
</tr>

<tr>
<td>1500</td>

<td>198.3</td>

<td>0.132</td>

<td>7.59</td>


<td>845</td>

<td>1945</td>

<td>2790</td>

<td>6.441</td>
</tr>

<tr>
<td>1600</td>


<td>201.4</td>

<td>0.124</td>

<td>8.03</td>

<td>859</td>

<td>1933</td>

<td>2792</td>


<td>6.418</td>
</tr>

<tr>
<td>1800</td>

<td>207.1</td>

<td>0.110</td>

<td>9.07</td>


<td>885</td>

<td>1910</td>

<td>2795</td>

<td>6.375</td>
</tr>

<tr>
<td>2000</td>


<td>212.4</td>

<td>0.0995</td>

<td>10.01</td>

<td>909</td>

<td>1889</td>

<td>2797</td>


<td>6.337</td>
</tr>

<tr>
<td>2100</td>

<td>214.9</td>

<td>0.0945</td>

<td>10.54</td>


<td>920</td>

<td>1878</td>

<td>2798</td>

<td>6.319</td>
</tr>

<tr>
<td>2300</td>


<td>219.6</td>

<td>0.0868</td>

<td>11.52</td>

<td>942</td>

<td>1858</td>

<td>2800</td>


<td>6.285</td>
</tr>

<tr>
<td>2400</td>

<td>221.8</td>

<td>0.0832</td>

<td>12.02</td>


<td>952</td>

<td>1849</td>

<td>2800</td>

<td>6.269</td>
</tr>

<tr>
<td>2600</td>


<td>226.0</td>

<td>0.0769</td>

<td>13.01</td>

<td>972</td>

<td>1830</td>

<td>2801</td>


<td>6.239</td>
</tr>

<tr>
<td>2700</td>

<td>228.1</td>

<td>0.0740</td>

<td>13.52</td>


<td>981</td>

<td>1821</td>

<td>2802</td>

<td>6.224</td>
</tr>

<tr>
<td>2900</td>


<td>232.0</td>

<td>0.0689</td>

<td>14.52</td>

<td>1000</td>

<td>1803</td>

<td>2802</td>


<td>6.197</td>
</tr>

<tr>
<td>3000</td>

<td>233.8</td>

<td>0.0666</td>

<td>15.00</td>


<td>1008</td>

<td>1794</td>

<td>2802</td>

<td>6.184</td>
</tr>

<tr>
<td>3200</td>


<td>237.4</td>

<td>0.0624</td>

<td>16.02</td>

<td>1025</td>

<td>1779</td>

<td>2802</td>


<td>6.158</td>
</tr>

<tr>
<td>3400</td>

<td>240.9</td>

<td>0.0587</td>

<td>17.04</td>


<td>1042</td>

<td>1760</td>

<td>2802</td>

<td>6.134</td>
</tr>

<tr>
<td>3600</td>


<td>244.2</td>

<td>0.0554</td>

<td>18.06</td>

<td>1058</td>

<td>1744</td>

<td>2802</td>


<td>6.112</td>
</tr>

<tr>
<td>3800</td>

<td>247.3</td>

<td>0.0524</td>

<td>19.08</td>


<td>1073</td>

<td>1728</td>

<td>2801</td>

<td>6.090</td>
</tr>

<tr>
<td>4000</td>


<td>250.3</td>

<td>0.0497</td>

<td>20.09</td>

<td>1087</td>

<td>1713</td>

<td>2800</td>


<td>6.069</td>
</tr>
</tbody>
</table>



""